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Clinical implementation of genetic testing in adults for hereditary hematologic malignancy syndromes

  • Safa Ansar
    Affiliations
    Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada
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  • Janet Malcolmson
    Affiliations
    Bhalwani Familial Cancer Clinic, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada

    Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
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  • Kirsten M. Farncombe
    Affiliations
    Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
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  • Karen Yee
    Affiliations
    Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada

    Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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  • Raymond H. Kim
    Correspondence
    Correspondence and requests for materials should be addressed to: Raymond H. Kim, Bhalwani Familial Cancer Clinic, 610 University Avenue 700U-6W390, Toronto, Ontario M5G 1Z5, Canada
    Affiliations
    Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada

    Bhalwani Familial Cancer Clinic, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada

    Ontario Institute for Cancer Research, Toronto, Ontario, Canada

    Division of Clinical and Metabolic Genetics, The Hospital for Sick Children, Toronto, Ontario, Canada

    Sinai Health System, Toronto, Ontario, Canada

    Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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  • Hassan Sibai
    Correspondence
    Hassan Sibai, Princess Margaret Cancer Centre, 610 University Avenue 700U-6-718, Toronto, Ontario M5G 1Z5, Canada.
    Affiliations
    Division of Medical Oncology and Hematology, Princess Margaret Cancer Centre, University Health Network, Toronto, Ontario, Canada

    Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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Open AccessPublished:September 18, 2022DOI:https://doi.org/10.1016/j.gim.2022.08.010

      Abstract

      Purpose

      As research on hereditary hematologic malignancy syndromes (HHMS) are accumulating, cancer genetics clinics are identifying more adult hematology patients with an inherited component to their disease. However, investigations for HHMS are complex, and there is no formal consensus on genetic testing criteria.

      Methods

      We developed genetic testing criteria for adult hematology patients through a comprehensive literature review and our experience at the Princess Margaret Cancer Centre. We validated our criteria by applying them retrospectively to patients referred to our clinic for HHMS assessment.

      Results

      Our genetic testing criteria are comprehensive of myeloid malignancies, lymphoid malignancies, and bone marrow failure, including age at diagnosis, family history, and genetic test results in blood and bone marrow. Of the 104 patients who met the criteria, 26% had at least 1 actionable variant in any gene associated with an increased risk of cancer and 13% had an actionable variant resulting in an HHMS diagnosis. A total of 15 patients had incidental findings, including 11 patients with a pathogenic variant associated with carrier status for an autosomal recessive disorder and 4 patients with a mosaic result.

      Conclusion

      Our high gene positivity rate shows the utility of a broad approach to germline testing in an adult hematology population.

      Keywords

      Introduction

      Although most hematologic malignancies (HMs) are thought to be related to spontaneous genetic changes in hematopoietic precursors, recent studies have reported a growing subset of patients with a strong hereditary component to their disease.
      • Furutani E.
      • Shimamura A.
      Germline genetic predisposition to hematologic malignancy.
      In contrast to sporadic HMs caused by somatic variants in only the hematologic system, an inherited HM is caused by a germline variant that may be shared between multiple family members. The use of clinical germline testing in a hematology context has grown rapidly over the last decade; since 2016, the World Health Organization has classified myeloid neoplasms with germline predispositions as distinct entities.
      • Arber D.A.
      • Orazi A.
      • Hasserjian R.
      • et al.
      The 2016 revision to the World Health Organization classification of myeloid neoplasms and acute leukemia.
      Although the awareness of inherited HMs is growing, many clinics have yet to include germline testing for patients with HMs as part of routine diagnostic workup.
      Germline genetic testing and counseling in this patient cohort can provide surveillance for at-risk family members, screen potential bone marrow donors, and inform therapeutic decision-making.
      • Furutani E.
      • Shimamura A.
      Germline genetic predisposition to hematologic malignancy.
      ,
      University of Chicago Hematopoietic Malignancies Cancer Risk Team
      How I diagnose and manage individuals at risk for inherited myeloid malignancies.
      ,
      • Desai A.V.
      • Perpich M.
      • Godley L.A.
      Clinical assessment and diagnosis of germline predisposition to hematopoietic malignancies: the University of Chicago experience.
      Unfortunately, because no formal consensus on germline testing criteria exists, recommendations are based on collective experience.
      University of Chicago Hematopoietic Malignancies Cancer Risk Team
      How I diagnose and manage individuals at risk for inherited myeloid malignancies.
      ,
      National Comprehensive Cancer Network, Myelodysplastic Syndromes V.3.2022, Updated January 13, 2022.
      • Baliakas P.
      • Tesi B.
      • Wartiovaara-Kautto U.
      • et al.
      Nordic guidelines for germline predisposition to myeloid neoplasms in adults: recommendations for genetic diagnosis, clinical management and follow-up.
      • Trottier A.M.
      • Godley L.A.
      Inherited predisposition to haematopoietic malignancies: overcoming barriers and exploring opportunities.
      • Kohlmann W.
      • Schiffman J.D.
      Discussing and managing hematologic germ line variants.
      • Babushok D.V.
      • Bessler M.
      Genetic predisposition syndromes: when should they be considered in the work-up of MDS?.
      Unlike solid tumor hereditary cancer syndromes (HCS), such as hereditary breast and ovarian cancer (HBOC) or Lynch syndrome, there are few guidelines for referrals for genetic counseling to implement clinical testing in adult patients. Moreover, testing for this hereditary component brings additional complexities, such as germline DNA tissue, phenotypic considerations, and follow-up functional assays.

      A brief overview of hereditary hematologic malignancy syndromes

      Hereditary hematologic malignancy syndromes (HHMS) are associated with multiple hematologic disorders, including HMs and nonmalignant hematologic disorders that affect the blood-forming tissues (Supplemental Figure 1). HHMS can be grouped into 2 broad categories: (1) HM predisposition syndromes and (2) inherited bone marrow failure syndromes (IBMFs) (Figure 1). In addition to HHMS, inherited predisposition to HMs can be associated with HCS in which HMs present alongside solid tumors.
      University of Chicago Hematopoietic Malignancies Cancer Risk Team
      How I diagnose and manage individuals at risk for inherited myeloid malignancies.
      ,
      National Comprehensive Cancer Network, Myelodysplastic Syndromes V.3.2022, Updated January 13, 2022.
      Figure thumbnail gr1
      Figure 1Classification of the most common HHMSs and hereditary cancer syndromes with a propensity for developing HMs. HHMSs include HM predisposition syndromes and inherited bone marrow failure syndromes. Inherited hematologic diseases, such as hemoglobinopathies and congenital thrombocytopenia, are outside the scope of this paper and have been excluded.
      • Kohne E.
      Hemoglobinopathies: clinical manifestations, diagnosis, and treatment.
      ,
      • Noris P.
      • Pecci A.
      Hereditary thrombocytopenias: A growing list of disorders.
      AA, aplastic anemia; AML, acute myeloid leukemia; HHMS, hereditary hematologic malignancy syndrome; HM, hematologic malignancy; MDS, myelodysplastic syndrome; MIRAGE, myelodysplasia, infection, restriction of growth, adrenal hypoplasia, genital phenotypes, and enteropathy.

      HM predisposition syndromes

      HM predisposition syndromes are associated with germline variants that confer an increased risk of malignancy, often with early-onset myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) occurring at <40 years of age.
      • Clifford M.
      • Bannon S.
      • Bednar E.M.
      • et al.
      Clinical applicability of proposed algorithm for identifying individuals at risk for hereditary hematologic malignancies.
      HM predisposition syndromes can be categorized based on whether they present with organ dysfunction and/or associated cytopenias. A brief overview of common HM predisposition syndromes can be found in Supplemental Table 1.

      IBMFs

      IBMFs are characterized by progressive bone marrow failure, congenital anomalies, and a predisposition to solid tumors and hematologic disorders, such as MDS and AML.
      • Porter C.C.
      • Druley T.E.
      • Erez A.
      • et al.
      Recommendations for surveillance for children with leukemia-predisposing conditions.
      Although most patients with IBMFs are diagnosed during childhood, some patients may present in adulthood with an HM, which is an important consideration when investigating inherited hematologic disorders in adults.
      • Babushok D.V.
      • Bessler M.
      Genetic predisposition syndromes: when should they be considered in the work-up of MDS?.
      Supplemental Table 2 lists a brief overview of IBMFs to consider during hereditary hematology workup.

      Hereditary lymphoid malignancies

      Acute lymphocytic leukemia (ALL) is the most common pediatric cancer representing approximately 25% of all malignant diseases in children.
      • Imamura T.
      Genetic alterations of pediatric acute lymphoblastic leukemia.
      Although most cases of ALL are sporadic in nature and uncommon in adults, it can occur as part of an HCS. In addition, pathogenic variants in IKZF1, SH2B3, and PAX5 have been described as segregating in families with ALL and are under consideration as new hereditary ALL genes, whereas RUNX1 and ETV6 (genes classically associated with HM predisposition syndromes) have been linked to cases of ALL (Supplemental Table 3). Individuals who have a first degree relative with lymphoma are noted to have a higher risk of developing Hodgkin’s lymphoma or non-Hodgkin’s lymphoma, suggesting a possible hereditary component to lymphomas.
      • Cerhan J.R.
      • Slager S.L.
      Familial predisposition and genetic risk factors for lymphoma.
      In addition, some lymphoma genes overlap with lymphoproliferative syndromes and primary immunodeficiency syndrome, such as X-linked lymphoproliferative syndrome (Duncan syndrome
      • Herber M.
      • Mertz P.
      • Dieudonné Y.
      • et al.
      Primary immunodeficiencies and lymphoma: a systematic review of literature.
      ).

      Hereditary myeloproliferative neoplasms

      Myeloproliferative neoplasms (MPNs) with progression to MDS or AML, including essential thrombocythemia, polycythemia rubra vera, primary myelofibrosis, and chronic myelomonocytic leukemia often present sporadically in patients with no family history.
      • Braunstein E.M.
      • Moliterno A.R.
      Back to biology: new insights on inheritance in myeloproliferative disorders.
      However, at least 7.6% of all patients with apparently sporadic myeloproliferative disorders are reported to have a family history of MPN.
      • Rumi E.
      • Passamonti F.
      • Della Porta M.G.
      • et al.
      Familial chronic myeloproliferative disorders: clinical phenotype and evidence of disease anticipation.
      Certain genes have been described as driving the familial inheritance of these MPNs (Supplemental Table 4). For example, germline pathogenic variants in JAK2 and MPL (common sporadic driver genes in MPNs) have been reported in some families.
      • Bellanné-Chantelot C.
      • Rabadan Moraes G.
      • Schmaltz-Panneau B.
      • Marty C.
      • Vainchenker W.
      • Plo I.
      Germline genetic factors in the pathogenesis of myeloproliferative neoplasms.
      Of note, a duplication on chromosome 14q has been observed segregating with disease through a family affected with myeloid malignancies, including MPN.
      • Hahn C.N.
      • Wee A.
      • Babic M.
      • et al.
      Duplication on chromosome 14q identified in familial predisposition to myeloid malignancies and myeloproliferative neoplasms.
      Although EGLN1 and EPAS1 genes have been linked to families with hereditary erythrocytosis or thrombocytosis, no single-gene familial MPN has been formally defined.
      • Bellanné-Chantelot C.
      • Rabadan Moraes G.
      • Schmaltz-Panneau B.
      • Marty C.
      • Vainchenker W.
      • Plo I.
      Germline genetic factors in the pathogenesis of myeloproliferative neoplasms.

      HCS associated with an increased risk of HM

      Some solid cancer predisposition syndromes are also associated with an increased risk of HM, including Li-Fraumeni syndrome (LFS). For example, in patients with LFS (pathogenic variant in TP53), the incidence of leukemia is reported to be approximately 4%, and patients may present with hypodiploid ALL.
      • Swaminathan M.
      • Bannon S.A.
      • Routbort M.
      • et al.
      Hematologic malignancies and Li-Fraumeni syndrome.
      In addition, early-onset MDS, AML, and lymphoid malignancies, such as ALL and lymphoma, have been reported in patients with other HCSs, including Lynch syndrome and HBOC.
      University of Chicago Hematopoietic Malignancies Cancer Risk Team
      How I diagnose and manage individuals at risk for inherited myeloid malignancies.
      However, evidence for associations between HMs and genes related to Lynch syndrome and HBOC are preliminary and still being defined.

      Other syndromes with an increased risk for HM

      Multiple congenital genetic syndromes have also been associated with an increased risk of MDS, AML, or childhood ALL development, including Noonan syndrome, Down syndrome (trisomy 21), ligase IV syndrome, and X-linked neutropenia, as well as the pediatric chromosomal instability syndromes, including Fanconi anemia (also classified as an IBMF), Bloom syndrome, ataxia telangiectasia, and Nijmegen breakage syndrome.
      • Furutani E.
      • Shimamura A.
      Germline genetic predisposition to hematologic malignancy.
      ,
      • Jongmans M.C.J.
      • Loeffen J.L.C.M.
      • Waanders E.
      • et al.
      Recognition of genetic predisposition in pediatric cancer patients: an easy-to-use selection tool.
      However, these syndromes present with other prominent clinical features that often warrant their own genetic testing workup outside of their hematologic manifestations.

      Genetic testing for HHMS

      Multiple testing strategies can be employed to investigate patients under suspicion for HHMS. Because the field is rapidly progressing, most available clinical testing is not inclusive of all genes that can be causative of HHMS. Although a comprehensive review of all genes associated with HHMS in the literature is beyond the scope of this article, we curated a list of genes available for HHMS germline testing on the basis of available commercial panels (Supplemental Table 5). In addition, the Clinical Genome Resource Myeloid Malignancy Variant Curation Expert Panel is currently evaluating variants associated with inherited risk for myeloid malignancies in all genes associated with HM predisposition syndromes (Figure 1). The Myeloid Malignancy Variant Curation Expert Panel’s curations will be extremely beneficial for the reporting and management of pathogenic variants in known HM predisposition genes.

      Germline tissue considerations for HHMS

      Selecting the appropriate tissue for germline analysis is particularly important when testing patients with a diagnosed HM for HHMS. Unlike genetic testing for solid tumor predisposition syndromes, blood-based genetic testing for HHMS will detect both somatic and germline variants because HHMS affects the blood-forming tissues. In addition, peripheral blood analysis may be further complicated by skewed clonal expansion of hematopoietic stem cells with somatic variants, a feature reported to occur both in patients with HM and healthy individuals, although, at a significantly higher percentage in older individuals (aged >65 years
      • Genovese G.
      • Kähler A.K.
      • Handsaker R.E.
      • et al.
      Clonal hematopoiesis and blood-cancer risk inferred from blood DNA sequence.
      ). Finally, because many patients with HMs receive a bone marrow transplant as part of their treatment, it is necessary to conduct genetic testing on their own germline DNA. As such, a sample from unaffected tissue is preferred. Recent literature agrees that the optimal tissue sample is cultured fibroblasts derived from a skin biopsy because other easily obtainable tissues (such as saliva, buccal swabs, or nails) can be contaminated with blood cells.
      • Desai A.V.
      • Perpich M.
      • Godley L.A.
      Clinical assessment and diagnosis of germline predisposition to hematopoietic malignancies: the University of Chicago experience.
      ,
      • DeRoin L.
      • Cavalcante De Andrade Silva M.
      • Petras K.
      • et al.
      Assessing the feasibility and limitations of cultured skin fibroblasts for germline genetic testing in hematologic disorders.

      Ancillary testing for HHMS

      Telomere length studies are a sensitive and specific test for the diagnosis of telomere biology disorders (TBDs) and can be a predictor of disease severity. Similarly, chromosome breakage studies may aid in the diagnosis of suspected chromosome instability syndromes, including Fanconi anemia, ataxia telangiectasia, or Nijmegen breakage syndrome. If individuals have undergone molecular testing that identified pathogenic variants in a TBD or chromosome instability syndrome, then these studies are not required for a diagnosis; however, the results may provide additional evidence in cases in which variants of uncertain significance (VUS) are identified.
      • DeZern A.E.
      • Churpek J.E.
      Approach to the diagnosis of aplastic anemia.
      ,
      • Alter B.P.
      • Rosenberg P.S.
      • Giri N.
      • Baerlocher G.M.
      • Lansdorp P.M.
      • Savage S.A.
      Telomere length is associated with disease severity and declines with age in dyskeratosis congenita.
      In this article, we performed a literature review to create genetic testing criteria for patients with a suspected HHMS informed by our clinic experience. We present clinical and family characteristics of adult hematology patients who were referred for genetics assessment and the germline positivity rate.

      Materials and Methods

      Developing genetic testing criteria for patients with a suspected HHMS

      We performed a literature search for existing germline testing criteria developed for HHMSs. Multiple searches were conducted with the most recent being in April 2022. In addition to disease-specific terms and genes (Supplemental Tables 1-4), our primary search terms included “hereditary,” “inherited,” “hematologic malignancy,” “germline,” “genetic testing,” and “criteria” or “recommendations.” Search terms were combined with each other and with the names of HHMS genes as needed to achieve comprehensive search results. The literature search was conducted using multiple platforms, including MEDLINE, Google Scholar, and PubMed. Guidelines from the National Comprehensive Cancer Network (https://www.nccn.org/guidelines/category_1) and GeneReviews (http://www.genereviews.org) were also consulted when applicable.
      We reviewed original research articles, case reports, systematic reviews, and clinical recommendations on germline testing in patients with inherited myeloid malignancies (MDS, AML, chronic myeloid leukemia), inherited lymphoid malignancies (ALL, chronic lymphocytic leukemia, Hodgkin’s lymphoma, non-Hodgkin’s lymphoma, multiple myeloma), inherited MPNs (essential thrombocythemia, polycythemia rubra vera, primary myelofibrosis, chronic myelomonocytic leukemia), and IBMFs (aplastic anemia). We also included search terms for HCS (Lynch syndrome, LFS, HBOC) and congenital disorders associated with an increased risk of HMs. We excluded the studies in which the primary focus was functional assays and the papers regarding inherited hemoglobinopathies or congenital thrombocytopenias because these were outside the scope of this study. Of the 228 documents identified in the literature, we identified 19 reports on clinical recommendations for germline testing in patients presenting with an HM. This included 2 guidelines from consensus groups (National Comprehensive Cancer Network and the Nordic MDS Study Group) and 17 recommendations from independent clinics/cancer centers. In total, 81 research articles were used to build our criteria (Supplemental Table 6).

      Patient population

      To evaluate the utility of our proposed referral criteria in a clinical context, we performed a retrospective chart review of all adult hematology patients who were referred to genetics, met our germline genetic testing criteria, and underwent panel testing for a hematologic indication between January 2015 and October 2021. The Princess Margaret Cancer Centre (PM) is the largest leukemia center in Canada and saw over 3000 adult patients with a malignant disorder from 2015 to 2021 (AML: 1597, MDS: 472, ALL: 286, MPN: 664, and bone marrow failure: 22). In 2018, we established a workflow to initiate germline genetic testing for all patients under the suspicion for an HHMS. This involved collaboration between the genetics clinic and the hematologists at PM to (1) capture patients on the basis of their personal/family history of cancer and suggestive genetic findings identified in blood/bone marrow, (2) procure a skin biopsy for fibroblast culture and germline DNA extraction, and (3) provide follow-up counseling and management recommendations for patients and their families.
      All patients referred to our clinic with a suspected HHMS were scheduled for a skin biopsy to gather tissue for germline genetic testing. The gold standard sampling method referred to in the literature and employed by our institution is a 3-mm skin-punch biopsy.
      University of Chicago Hematopoietic Malignancies Cancer Risk Team
      How I diagnose and manage individuals at risk for inherited myeloid malignancies.
      Biopsy material was cultured for 3 to 4 weeks, resulting in a skin fibroblast cell line that was sent directly to testing facilities for DNA extraction and analysis via commercially available gene panels.
      Some patients in our institution diagnosed with a myeloid malignancy underwent blood/bone marrow cytogenetic testing and next-generation sequencing (NGS) to identify any chromosomal or single-gene aberrations that may influence patient prognosis and treatment plans. We used these results to inform germline genetic strategy because pathogenic variants in certain genes may be suggestive of an inherited hematologic disorder.

      Results

      Genetic testing criteria for patients with a suspected HHMS

      Consensus for referral criteria was achieved after a review by all authors, and detailed rationale for each criterion can be found in Supplemental Table 6.
      In brief, we recommend genetic testing in all patients with a personal history of MDS, AML, or progressive bone marrow failure at age ≤40 years (Table 1). Recommendations in the literature suggest testing all patients presenting at either ≤40 or ≤50 years of age.
      National Comprehensive Cancer Network, Myelodysplastic Syndromes V.3.2022, Updated January 13, 2022.
      • Baliakas P.
      • Tesi B.
      • Wartiovaara-Kautto U.
      • et al.
      Nordic guidelines for germline predisposition to myeloid neoplasms in adults: recommendations for genetic diagnosis, clinical management and follow-up.
      • Trottier A.M.
      • Godley L.A.
      Inherited predisposition to haematopoietic malignancies: overcoming barriers and exploring opportunities.
      ,
      • Babushok D.V.
      • Bessler M.
      Genetic predisposition syndromes: when should they be considered in the work-up of MDS?.
      ,
      • Clifford M.
      • Bannon S.
      • Bednar E.M.
      • et al.
      Clinical applicability of proposed algorithm for identifying individuals at risk for hereditary hematologic malignancies.
      ,
      • Mangaonkar A.A.
      • Patnaik M.M.
      Hereditary predisposition to hematopoietic neoplasms: when bloodline matters for blood cancers.
      • DiNardo C.D.
      • Routbort M.J.
      • Bannon S.A.
      • et al.
      Improving the detection of patients with inherited predispositions to hematologic malignancies using next-generation sequencing-based leukemia prognostication panels.
      • Tawana K.
      • Brown A.L.
      • Churpek J.E.
      Integrating germline variant assessment into routine clinical practice for myelodysplastic syndrome and acute myeloid leukaemia: current strategies and challenges.
      • Roloff G.W.
      • Drazer M.W.
      • Godley L.A.
      Inherited susceptibility to hematopoietic malignancies in the era of precision oncology.
      Although most recommendations suggest a cut-off of ≤50 years, we opted to prioritize patients with an isolated disease at <40 years because the incidence of MDS rapidly increases with age.
      • Babushok D.V.
      • Bessler M.
      Genetic predisposition syndromes: when should they be considered in the work-up of MDS?.
      ,
      Leukemia and Lymphoma Society. Myelodysplastic syndromes. Leukemia and Lymphoma Society; Published 2019. Updated 2022.
      We also recommend testing all adult patients with a personal history of hypodiploid ALL diagnosed at age ≤18 years because a large percentage of these individuals are found to have a causal germline TP53 variant.
      • Holmfeldt L.
      • Wei L.
      • Diaz-Flores E.
      • et al.
      The genomic landscape of hypodiploid acute lymphoblastic leukemia.
      Table 1Proposed germline genetic testing referral criteria for hereditary hematologic malignancy syndromes
      Referral CriterionDescription
      1Personal history of
      • MDS, AML (excluding core binding/APL)
        AML excluding de novo AML with core binding factors t(8;21) or inv(16)/APL.
        , or progressive bone marrow failure
        Bone marrow failure includes aplastic anemia or prolonged unexplained pancytopenia.
        diagnosed at ≤40 years of age
      • hypodiploid ALL diagnosed at ≤18 years of age
      2Personal history of MDS, AML
      AML excluding de novo AML with core binding factors t(8;21) or inv(16)/APL.
      , or progressive bone marrow failure
      Bone marrow failure includes aplastic anemia or prolonged unexplained pancytopenia.
      diagnosed at ≤50 years of age with
      • cytogenetic aberrations in chromosome 7 [monosomy7/del(7q)/der(7)] seen in blood/bone marrow
      • chronic low blood cell counts/cytopenias and/or bleeding tendency suggestive of a platelet function disorder
      • severe and unusual infections or immunodeficiency
      • cutaneous or mucocutaneous findings (eg, cafe-au-lait spots, skin hypopigmentation, nail dystrophy, oral leukoplakia)
      • congenital anomalies (limb abnormalities, heart/kidney defects, microcephaly, facial dysmorphism, short stature, skeletal dysplasia, dental abnormalities, unexplained deafness)
      3
      • Personal history of any myeloid malignancy
        Myeloid malignancy includes MDS, AML (note aforementioned exclusion), and CML.
        , lymphoid malignancy
        Lymphoid malignancy includes multiple myeloma, ALL, CLL, HL, and NHL.
        , or bone marrow failure
        Bone marrow failure includes aplastic anemia or prolonged unexplained pancytopenia.
        at any age with one of the following:
      • 1 first degree relative with a shared clinical presentation/hematologic diagnosis
      • 2 close relatives
        Close relatives typically include first, second, and third degree blood relatives.
        with any myeloid malignancy
        Myeloid malignancy includes MDS, AML (note aforementioned exclusion), and CML.
        , lymphoid malignancy
        Lymphoid malignancy includes multiple myeloma, ALL, CLL, HL, and NHL.
        , or bone marrow failure
      4Personal history of any myeloid malignancy
      Myeloid malignancy includes MDS, AML (note aforementioned exclusion), and CML.
      , lymphoid malignancy
      Lymphoid malignancy includes multiple myeloma, ALL, CLL, HL, and NHL.
      , or bone marrow failure
      Bone marrow failure includes aplastic anemia or prolonged unexplained pancytopenia.
      at any age and a personal history of ≥2 additional cancers
      Adrenocortical carcinoma, brain tumors, sarcomas, male/female breast cancer, gynecologic malignancies, genitourinary cancers, lung carcinoma (nonsmokers), endocrine cancer, gastrointestinal cancers, and multiple skin cancers.
      , including squamous cell carcinoma of head, neck, or anogenital tract
      5
      • Personal history of erythrocytosis or MPN
        MPN includes ET, PRV, PMF, CMML.
        at any age with one of the following:
      • 1 first degree relative with a shared clinical presentation
      • 2 close relatives
        Close relatives typically include first, second, and third degree blood relatives.
        with any MPN or myeloid malignancy
      6Personal history of any myeloid malignancy
      Myeloid malignancy includes MDS, AML (note aforementioned exclusion), and CML.
      , bone marrow failure
      Bone marrow failure includes aplastic anemia or prolonged unexplained pancytopenia.
      , lymphoid malignancy
      Lymphoid malignancy includes multiple myeloma, ALL, CLL, HL, and NHL.
      , or MPN
      MPN includes ET, PRV, PMF, CMML.
      and a pathogenic/likely pathogenic variant seen in blood/bone marrow, with a VAF of ≥5% in one of the following genes: ANKRD26, CEBPA, DDX41, ETV6, GATA2, RUNX1, SH2B3, SRP72, TERC, and TERT; or has a result on telomere length testing/chromosome breakage analysis suggestive of telomere biology disorders/chromosome instability syndromes
      7Personal history of any myeloid malignancy
      Myeloid malignancy includes MDS, AML (note aforementioned exclusion), and CML.
      , bone marrow failure
      Bone marrow failure includes aplastic anemia or prolonged unexplained pancytopenia.
      , lymphoid malignancy
      Lymphoid malignancy includes multiple myeloma, ALL, CLL, HL, and NHL.
      , or MPN
      MPN includes ET, PRV, PMF, CMML.
      and
      • fulfills testing criteria for other hereditary cancer syndromes (eg, Li-Fraumeni syndrome, Lynch syndrome, hereditary breast and ovarian cancer syndrome)
        Based on Ontario Health Hereditary Cancer Testing Eligibility Criteria.
      • has a family member with a germline pathogenic/likely pathogenic variant in any hereditary cancer gene
      ALL, acute lymphocytic leukemia; AML, acute myeloid leukemia; APL, acute promyelocytic leukemia; CLL, chronic lymphocytic leukemia; CML, chronic myeloid leukemia; CMML, chronic myelomonocytic leukemia; ET, essential thrombocythemia; HL, Hodgkin’s lymphoma; MDS, myelodysplastic syndrome; MPN, myeloproliferative neoplasm; NHL, non-Hodgkin’s lymphoma; PMF, primary myelofibrosis; PRV, polycythemia rubra vera; VAF, variant allele fraction.
      a AML excluding de novo AML with core binding factors t(8;21) or inv(16)/APL.
      b Bone marrow failure includes aplastic anemia or prolonged unexplained pancytopenia.
      c Myeloid malignancy includes MDS, AML (note aforementioned exclusion), and CML.
      d Lymphoid malignancy includes multiple myeloma, ALL, CLL, HL, and NHL.
      e Close relatives typically include first, second, and third degree blood relatives.
      f Adrenocortical carcinoma, brain tumors, sarcomas, male/female breast cancer, gynecologic malignancies, genitourinary cancers, lung carcinoma (nonsmokers), endocrine cancer, gastrointestinal cancers, and multiple skin cancers.
      g MPN includes ET, PRV, PMF, CMML.
      h Based on Ontario Health Hereditary Cancer Testing Eligibility Criteria.
      We consider the 41 to 50 years age group if additional suggestive features are present, including cytogenetic aberrations in chromosome 7 (including monosomy7, del[7q], and der[7] seen in blood/bone marrow), chronic low blood counts/cytopenias or bleeding tendency suggestive of a platelet function disorder, severe and unusual infections/immunodeficiency, cutaneous or mucocutaneous findings, and congenital anomalies because these are well-documented phenomenon of known HHMS and other congenital genetic syndromes associated with HMs.
      University of Chicago Hematopoietic Malignancies Cancer Risk Team
      How I diagnose and manage individuals at risk for inherited myeloid malignancies.
      Notably, not all patients with an HHMS will present before age 50 years.
      • Bannon S.A.
      • Routbort M.J.
      • Montalban-Bravo G.
      • et al.
      Next-generation sequencing of DDX41 in myeloid neoplasms leads to increased detection of germline alterations.
      ,
      • Sébert M.
      • Passet M.
      • Raimbault A.
      • et al.
      Germline DDX41 mutations define a significant entity within adult MDS/AML patients.
      After a review of multiple case and cohort studies, we determined that patients with a personal history of myeloid malignancy, lymphoid malignancy, or bone marrow failure at any age should be tested for HHMS if they have 1 first degree relative with a shared clinical presentation/hematologic diagnosis or 2 close relatives diagnosed with a myeloid malignancy, lymphoid malignancy, or bone marrow failure at any age. Although no criteria for familial lymphoid malignancies have been defined, individual cases and family cohort studies suggest that a hereditary component to these diseases may exist. Similarly, although no criteria for familial MPNs have been defined, a first degree relative with shared clinical presentation or 2 close relatives with any MPN or myeloid malignancy are more likely to indicate an inherited MPN. We also recommend testing in patients of any age with a personal history of 2 or more solid tumors in addition to their HM that are commonly described in HCSs or other syndromes associated with HMs.
      Not all individuals with an HHMS present with a family history given that the HHMS may be de novo or may have incomplete penetrance.
      • Sébert M.
      • Passet M.
      • Raimbault A.
      • et al.
      Germline DDX41 mutations define a significant entity within adult MDS/AML patients.
      Thus, we recommend germline testing in patients with pathogenic/likely pathogenic variants seen in 10 HHMS-related genes in blood/bone marrow (with a variant allele fraction of ≥5% to account for detection limits of most NGS platforms
      • Kim J.
      • Kim D.
      • Lim J.S.
      • et al.
      The use of technical replication for detection of low-level somatic mutations in next-generation sequencing.
      ). In accordance with previously published criteria and known strategies for diagnosing TBDs and chromosome instability syndromes, we also recommend germline testing in individuals with abnormal results on telomere length studies or chromosome breakage analysis.
      • DiNardo C.D.
      • Routbort M.J.
      • Bannon S.A.
      • et al.
      Improving the detection of patients with inherited predispositions to hematologic malignancies using next-generation sequencing-based leukemia prognostication panels.
      Finally, recommendations for individuals who fit other genetic testing criteria are included to ensure referral to genetics in cases in which a patient presents with an HM as part of an HCS, has a family history suggestive of an HCS, or has a family member with a known pathogenic variant.

      Determining the clinical utility of our genetic testing criteria

      Of the 116 patients who were referred for a suspected HHMS between 2015 and 2021, 104 patients (59 males, 45 females) met our proposed genetic testing criteria. A total of 63 patients (61%) were aged ≤50 years and 41 patients (39%) were aged >50 years at the time of their first hematologic diagnosis (age range: 1-81 years, median = 41 years). A total of 70 patients (67%) were referred with a positive family history of hematologic disorders. In addition, 55 patients presented with a myeloid malignancy (43 with MDS or AML and 12 with an MPN), 38 presented with a lymphoid malignancy (ALL, chronic lymphocytic leukemia, or lymphoma), 8 presented with bone marrow failure, and 3 presented with other hematologic disorders (Table 2). Of note, 54 (52%) patients received NGS of blood/bone marrow and 21 (20%) received telomere length and/or chromosome breakage studies as part of their diagnostic workup.
      Table 2Characteristics of 27 patients with an actionable result after germline testing
      Patients diagnosed with an HHMS
      Referral CriterionSexPrimary Classification of HMHM DiagnosisAge at HM Diagnosis, yOther Clinical HistoryFamily History of HMTL/CB StudiesRelevant Pathogenic Variants Found in Blood/Bone Marrow NGS (VAF ≥5%)Germline Result and VariantDiagnosis
      1MIBMFAplastic anemia24Benign squamous papilloma (gingival), benign thyroid massNTL not suggestive of TBD, CB suggestive of Fanconi anemiaNot performedFANCG (NM_004629.2)

      (homozygous), (c.1077-7T>G)



      RBM8A (NM_005105.5)

      (c.-21G>A)
      Fanconi anemia
      1MIBMFPancytopenia27N/AYTL not suggestive of TBD, CB normalNot performedRPS10 (NM_001014.5)

      (c.292dup, p.Arg98Profs∗10)
      Diamond-Blackfan anemia
      1FIBMFPlatelet dysfunction and platelet storage and pool disease30N/AYNot performedNot performedRUNX1 (NM_001754.5)

      (c.968-2725_∗217delinsGTTTCTA)
      Familial platelet disorder with mutated RUNX1
      1, 3MMyeloidAML, relapsed MDS23, 32Pulmonary fibrosisYNot performedNot performedRTEL1 (NM_032957.5)

      (c.3034C>T, p.Gln1012∗)
      Telomere biology disorder (previously called dyskeratosis congenita)
      1, 3, 6MLymphoidT cell ALL, AML/mixed phenotypic acute leukemia
      Indicates dual HM.
      17, 35N/AYNot performedRUNX1 (NM_001754.5)

      (c.1003C>T, p.Gln335∗ 52%)
      RUNX1 (NM_001754.5)

      (c.1003C>T, p.Gln335∗)
      Familial platelet disorder with mutated RUNX1
      1, 3, 6, 7MMyeloidAML31Platelet dysfunction in childhoodYNot performedCEBPA (NM_004364.5)

      (c.464_471delinsCCTGTC, p.Leu155Profs∗14 29%)

      RUNX1 (NM_001754.5)

      (c.601C>T, p.Arg201∗ 49%)

      RUNX1 (NM_001754.5) (c.497_498insTCC, p.Arg166_Ser167insPro 57%)
      RUNX1 (NM_001754.5)

      (c. 601C>T, p.Arg201∗)
      Familial platelet disorder with mutated RUNX1
      2, 3MMyeloidThrombocytopenia, MDS, secondary AML, post-transplant lymphoproliferative disorder
      Indicates dual HM.
      20s, 45, 48Chronic low blood counts/cytopeniaYNot performedNoneETV6 (NM_001987.5)

      (c.1153-1_1165del, p.Asn385Valfs∗7)

      DDX41 (NM_016222.4)

      (c.1187T>C, p.Ile396Thr)
      ETV6-related thrombocytopenia and familial MDS/AML with mutated DDX41
      3MLymphoidNHL14Hypogammaglobulinemia, recurrent infectionsYNot performedNot performedSH2D1A (NM_002351.5)

      (c.201+3A>G, splice donor variant)
      X-linked lymphoproliferative disease (Duncan syndrome)
      3MMyeloidPancytopenia, AML59N/AYNot performedNoneDDX41 (NM_016222.4)

      (c.1142dup, p.Ile382Aspfs∗6)
      Familial MDS/AML with mutated DDX41
      3FMyeloidPre-MDS (early MDS)69N/AYTL not performed, CB normalETV6 (NM_001987.5) (c.1132C>T (p.Arg378∗ 52%)ETV6 (NM_001987.5)

      (c.1132C>T, p.Arg378∗)
      ETV6-related thrombocytopenia
      3, 6MLymphoidDiffuse large B cell lymphoma, AML
      Indicates dual HM.
      48, 48N/AYTL suggestive of TBDRUNX1 (NM_001754.5) (c.497G>A, p.Arg166Gln 39%)RTEL1 (NM_032957.5)

      (c.1207+1G>A, splice donor variant)
      Telomere biology disorder (previously called dyskeratosis congenita)
      5FMPNErythrocytosis (suspected PRV)48Adrenal adenomaYNot performedNoneEGLN1 (NM_022051.3)

      (c.715C>T; p.Gln239∗)
      EGLN-related familial erythrocytosis
      6MMyeloidAML54Melanoma, thalassemiaYNot performedDDX41 (NM_016222.4) (c.986del, p.Gln329Argfs∗7 47%)DDX41 (NM_016222.4)

      (c.986del, p.Gln329Argfs∗7)
      Familial MDS/AML with mutated DDX41
      Patients diagnosed with nonhematologic HCS
      1, 3FMyeloidMacrocytic anemia, hypocellular marrow (early MDS)24N/AYTL not suggestive of TBD, CB normalNonePMS2
      Indicates patients with a known familial pathogenic variant before HHMS testing.
      (NM_000535.5)

      (c.164-?_2589+?del)
      Lynch syndrome
      2FMyeloidMacrocytic anemia and neutropenia, early MDS46Chronic low blood counts/cytopeniaNTL not suggestive of TBD, CB normalNot performedBRIP1 (NM_032043.3)

      (c.2990_2993del, p.Thr997Argfs∗61)
      BRIP1
      3MLymphoidCLL45Testicular cancerYNot performedNoneCHEK2 (NM_007194.4)

      (c.470T>C, p.Ile157Thr)
      CHEK2
      3FLymphoidMultiple myeloma58N/AYNot performedNot performedFH (NM_000143.4)

      (c.1431_1433dup, p.Lys477dup)
      Hereditary leiomyomatosis and renal cell cancer
      3FLymphoidMultiple myeloma38N/AYNot performedNot performedCHEK2 (NM_007194.4)

      (c.470T>C, p.Ile157Thr)
      CHEK2
      3, 4MLymphoidB cell NHL61Papillary thyroid carcinoma, right parietal astrocytoma, liver hemangiomaYNot performedNot performedATM (NM_000051.4)

      (c.2250G>A, p.Lys750=)
      ATM
      3, 7MMyeloidMyelofibrosis, secondary AML61, 65N/AYNot performedNoneBRCA1
      Indicates patients with a known familial pathogenic variant before HHMS testing.
      (NM_007294.4)

      (c.5266dup, p.Gln1756Profs∗74)

      RBM8A (NM_005105.5)

      (c.-21G>A)
      Hereditary breast and ovarian cancer syndrome
      4FLymphoidB cell ALL81Bladder cancer, mesotheliomaNNot performedNot performedBAP1 (NM_004656.4)

      (c.758dup, p.Thr254Aspfs∗30)
      BAP1-tumor predisposition syndrome
      4FLymphoidCLL51Papillary thyroid cancer, breast cancerNNot performedNot performedMITF (NM_000248.4)

      (c.952G>A, p.Glu318Lys)
      MITF
      4, 7FLymphoidB cell ALL, relapsed B cell ALL71, 76Renal cell carcinoma, metastatic ovarian cancerNNot performedNoneBRCA1 (NM_007294.4)

      (c.5266dup, p.Gln1756Profs∗74)
      Hereditary breast and ovarian cancer syndrome
      6, 7MMyeloidMDS68N/ANNot performedNoneBRCA1 (NM_007294.4)

      (c.5074G>C, p.Asp1692His)
      Hereditary breast and ovarian cancer syndrome
      7FLymphoidB-cell ALL28Breast angiosarcomaYNot performedNonePALB2
      Indicates patients with a known familial pathogenic variant before HHMS testing.
      (NM_024675.3)

      (c.2835-?_3113+?del, p.Ala946_Trp1038del)
      PALB2
      7FMyeloidTherapy-related AML62Clear cell renal cell carcinoma, breast cancerNNot performedNoneCHEK2
      Indicates patients with a known familial pathogenic variant before HHMS testing.
      (NM_007194.4)

      (c.320-1G>T, splice acceptor variant)

      RBM8A (NM_005105.5)

      (c.-21G>A)
      CHEK2
      7MMyeloidAcute promyelocytic leukemia39Rectal cancerNNot performedNoneMSH2
      Indicates patients with a known familial pathogenic variant before HHMS testing.
      (NM_000251.3)

      (c.1147C>T, p.Arg383∗)
      Lynch syndrome
      Relevant pathogenic variants found in blood/bone marrow (tumor testing results) include variants in the 10 genes listed in our referral criteria. ALL, acute lymphocytic leukemia; AML, acute myeloid leukemia; CB, chromosome breakage; CLL, chronic lymphocytic leukemia; F, female; HCS, hereditary cancer syndrome; HHMS, hereditary hematologic malignancy syndrome; HM, hematologic malignancy; IBMF, inherited bone marrow failure; M, male; MDS, myelodysplastic syndrome; MPN, myeloproliferative neoplasm; N, no; N/A, not applicable; NHL, non-Hodgkin’s lymphoma; NGS, next-generation sequencing; PRV, polycythemia rubra vera; TBD, telomere biology disorder; TL, telomere length; VAF, variant allele fraction; Y, yes.
      a Indicates dual HM.
      b Indicates patients with a known familial pathogenic variant before HHMS testing.
      A flowchart of our analysis and the frequency of individual testing criteria that each patient met is presented in Figure 2. In total, 27 (26%) patients referred had at least 1 actionable result, in which actionability is defined by the presence of a pathogenic variant in any gene associated with an increased cancer risk. Of these 27 positive cases, 13 (13% of all referrals) occurred in a gene associated with HMs and resulted in an HHMS diagnosis, and 14 patients were found to have a variant in a gene associated with a nonhematologic HCS. Notably, 4 of the 13 (31%) patients with a HHMS diagnosis were found to have the same variant in germline testing as discovered in NGS of blood/bone marrow. Characteristics, including genetic result, HHMS diagnosis, results from NGS in blood/bone marrow (if applicable), and ancillary testing modalities (if applicable) are summarized for these patients in Table 2.
      Figure thumbnail gr2
      Figure 2Breakdown of results from our Princess Margaret cohort. A. Of the 116 patients referred for HHMS workup, 104 fitted genetic testing criteria and were included in our analysis. A total of 12 patients who did not meet the criteria were excluded (no significant personal history of other cancers, no significant family history of hematologic malignancies, no suspicious variants on tumor testing). Of the 104 patients included in our analysis, 14 pathogenic variants in an HHMS gene were found in 13 patients, indicating that 1 patient had 2 pathogenic variants and 2 concurrent diagnoses. A total of 14 patients were found to have an actionable variant in a nonhematologic hereditary cancer gene. B. Of the 104 patients included in our analysis, 26 patients met multiple referral criteria, with criterion 3 being the most frequently met criterion for inclusion. Of the 7 patients included under criterion 2 in the 40 to 50 years age group, 2 patients met criterion 2 owing to a cytogenetic aberration in chromosome 7 (monosomy 7) and 5 patients met criterion 2 owing to chronic low blood cell counts/cytopenias suggestive of a platelet function disorder. No patients who met criterion 2 had immunodeficiency or cutaneous or congenital anomalies. AML, acute myeloid leukemia; HHMS, hereditary hematologic malignancy syndrome; MDS, myelodysplastic syndrome.
      When further analyzed by specific diagnoses, this corresponded to a positive genetic result in 28% of referred patients with MDS/AML, 29% of referred patients with a lymphoid malignancy, and 33% of referred patients with bone marrow failure, MPN, or other hematologic disorders. In addition, 19 (70%) patients with an actionable variant had a positive family history of HMs, whereas 8 (30%) presented with no family history of HMs. Of the 18 patients referred to genetics with >2 primary malignancies in addition to an HM, 5 (28%) had an actionable germline result. Of the 41 patients referred at age >50 years, 11 (27%) patients were found to have an actionable germline result.
      A total of 15 patients had incidental findings, including 11 patients who had a pathogenic variant associated with carrier status for an autosomal recessive disorder. This number also included 4 patients with a mosaic result, all of whom were biopsied over age 70 years, indicating that the identified pathogenic variant could represent somatic variation in their skin (2 NF1, 1 APC, and 1 RAD51C
      • Hernando B.
      • Dietzen M.
      • Parra G.
      • et al.
      The effect of age on the acquisition and selection of cancer driver mutations in sun-exposed normal skin.
      ). Out of 104 patients, 68 (65%) patients were found to have at least 1 VUS.
      Reports of dual HMs (defined as patients diagnosed with synchronous dual HMs who present with 2 clonally unrelated malignancies) are rare in the literature and suspected to be under-reported because they may be masked by the primary malignancy.
      • Kotchetkov R.
      • Ellison E.
      • McLean J.
      • Pressnail B.
      • Nay D.
      Synchronous dual hematological malignancies: new or underreported entity?.
      Of the 27 patients with an actionable germline result, we report 3 individuals (13%) with dual HM.

      Discussion

      HHMSs are emerging clinical entities with a growing body of literature. In this article, we report our experience in developing comprehensive HHMS genetic testing criteria and their implementation in adult hematology patients seen at the PM. In a cohort of 104 patients with HMs who met criteria for germline genetic testing, 27 patients (26%) had an actionable result in a hereditary cancer gene, including 13 (13%) patients who were diagnosed with an HHMS, which is similar to the rates reported in the literature.
      University of Chicago Hematopoietic Malignancies Cancer Risk Team
      How I diagnose and manage individuals at risk for inherited myeloid malignancies.
      ,
      • DiNardo C.D.
      • Bannon S.A.
      • Routbort M.
      • et al.
      Evaluation of patients and families with concern for predispositions to hematologic malignancies within the hereditary hematologic malignancy clinic (HHMC).
      ,
      • Kim B.
      • Yun W.
      • Lee S.T.
      • et al.
      Prevalence and clinical implications of germline predisposition gene mutations in patients with acute myeloid leukemia.
      However, these studies reported smaller cohorts or were focused on patients diagnosed with MDS, AML, or bone marrow failure. For the 13 patients in our cohort who had a pathogenic variant identified in an HHMS gene, their genetic test result provided an explanation for their HM diagnosis. Implications of actionable germline pathogenic variants include selection of an appropriate donor for bone marrow transplant, ongoing surveillance, and counseling on the importance of this information for their family members. Of note, owing to the recessive nature of some HHMSs, a 3-generation family history and consanguinity assessment is merited.
      Providing genetic counseling is particularly important given that panel genetic testing for HHMS tends to be broad and can provide patients with more information than just an HHMS diagnosis. Given the role of many solid tumor HCS genes contributing to HHMS, many gene panels could result in an unexpected diagnosis of a solid tumor HCS. In our cohort, we diagnosed 14 individuals with a solid tumor HCS, 5 of whom were unexpected given that they did not meet existing HCS criteria. In addition, given that HHMS panels are large and include preliminary evidence genes, they can also result in the identification of multiple pathogenic variants, numerous VUS (68 patients), or incidental findings, such as variants associated with carrier status for an autosomal recessive disorder (11 patients). Another incidental finding that can be detected through NGS includes possible mosaic pathogenic variants that are detected at low allele fractions, which could be suggestive of an acquired genetic change (4 patients
      • Chao E.C.
      • Astbury C.
      • Deignan J.L.
      • et al.
      Incidental detection of acquired variants in germline genetic and genomic testing: a points to consider statement of the American College of Medical Genetics and Genomics (ACMG).
      ).
      In 2018, we streamlined HHMS referrals through collaboration between the genetics clinic and PM hematologists. After the implementation of this workflow, we saw an increase in the total number of referrals over the past 7 years, with 24 patients (5 actionable cases) referred between 2015 and 2018 and 80 patients (22 actionable cases) referred between 2019 and 2021. However, these could be an underestimation of patients fulfilling the criteria because most of the 104 patients who underwent testing for HHMS were diagnosed with an HM at a young age or had a family history of HMs, which could reflect ascertainment bias in those who were referred to our clinic. Owing to this, additional unknown clinical factors contributing to HHMS may not be fully captured. By implementing our criteria, we hope to raise awareness on the importance of genetic testing in a hematology population. We anticipate that our broad criteria will help provide insight on the true positivity rate for specific groups of patients with HMs, including patients with lymphoid malignancies and MPNs, individuals diagnosed with an HM at an older age, patients referred because of the findings in NGS of blood/bone marrow, and patients referred under suspicion for syndromes involving multiple primary cancers. Furthermore, comparing our diagnostic yield to future studies on unselected populations will be informative on the validity of our proposed criteria and determine the frequency of variants in less penetrant genes.
      Although multiple centers have developed genetic testing criteria in a hereditary hematology context, most criteria are focused on patients who present with MDS/AML or bone marrow failure. In contrast, our genetic testing criteria were designed through an extensive literature review to be comprehensive of all myeloid malignancies, including MPNs, lymphoid malignancies, and nonmalignant disorders of the bone marrow. Interestingly, 1 out of 12 (8%) referred patients with an MPN in our cohort was positive. This is likely due to under-referral in this population based on our small sample size and the preliminary nature of hereditary MPN literature. Of the 38 referred patients with a lymphoid malignancy, 11 (29%) patients were found to have an actionable germline variant (3 in an HHMS gene and 8 in an HCS gene), highlighting the importance of testing in this patient population.
      Many of the conditions identified in our adult population were traditionally thought to be related to syndromic forms often diagnosed in childhood (Fanconi anemia, TBDs, and Diamond-Blackfan anemia) and have significant implications for cancer screening and surveillance.
      • Jongmans M.C.J.
      • Loeffen J.L.C.M.
      • Waanders E.
      • et al.
      Recognition of genetic predisposition in pediatric cancer patients: an easy-to-use selection tool.
      Although HHMS genes that are not well characterized (RUNX1, DDX41, and ETV6) may not have clear surveillance guidelines, regular complete blood count monitoring and bone marrow biopsies may avoid complications, such as bleeding and hemorrhage, and presentation at late stages of an HM.
      University of Chicago Hematopoietic Malignancies Cancer Risk Team
      How I diagnose and manage individuals at risk for inherited myeloid malignancies.
      ,
      • Desai A.V.
      • Perpich M.
      • Godley L.A.
      Clinical assessment and diagnosis of germline predisposition to hematopoietic malignancies: the University of Chicago experience.
      As data accumulates in these understudied HHMS genes, further surveillance recommendations and therapies may emerge. Importantly, it is essential to identify an HHMS in a patient who will undergo an allogeneic bone marrow transplant to avoid an affected donor relative.
      Despite the substantial literature and a growing clinical awareness of inherited HMs, many clinics have yet to include germline testing for these patients as part of routine diagnostic workup. This is likely because of barriers to HHMS testing, such as the logistics of sample procurement. For example, not all clinics are able to obtain skin biopsies, and the additional step of fibroblast culture adds 1 to 2 months to the turnaround time compared with the genetic testing of blood for solid tumor HCS. Similarly, the lack of consensus criteria leaves panel testing inaccessible and inconsistent for patients with HMs. These issues will be addressed with time as HHMS testing becomes broadly integrated with routine clinical practice.
      In summary, the genetic testing criteria we propose are based on both our experience with HHMS and a thorough review of the known hereditary associations with myeloid malignancies, lymphoid malignancies, and bone marrow failure syndromes. Future multicenter prospective studies for each malignant disease are needed to further validate and refine our proposed germline testing criteria. Overall, our high gene positivity rate in patients with HMs across a wide age range and the increase in the number of referrals to genetics service suggests that there is a demand for providing this service to patients with HMs. A broad approach to genetic testing criteria that includes age of diagnosis, family history, and genetic test results from bone marrow studies will be beneficial because it expands access to genetic testing, which in turn will further our knowledge in the constantly evolving field of HHMS.

      Data Availability

      All actionable variants found in the study are reported in Table 2.

      Conflict of Interest

      The authors declare no conflict of interest.

      Acknowledgments

      H.S. is generously supported by the Princess Margaret Cancer Foundation, Canada , Anna-Liisa and Graham Farquharson Blood Disorders Genetics Fund, and the Jain Family Fund. R.H.K. is supported by The Bhalwani Family Charitable Foundation.

      Author Information

      Conceptualization: R.H.K., H.S.; Data Curation: S.A., J.M.; Formal Analysis: S.A., J.M., K.Y., R.H.K., H.S.; Funding Acquisition: R.H.K., H.S.; Investigation: S.A., J.M., R.H.K., H.S.; Methodology: S.A., J.M., R.H.K., H.S.; Project Administration: K.M.F., R.H.K., H.S.; Supervision: R.H.K., H.S.; Visualization: S.A., J.M.; Writing-original draft: S.A., J.M., K.M.F., R.H.K., H.S.; Writing-review and editing: S.A., J.M., K.M.F., K.Y., R.H.K., H.S.

      Ethics Declaration

      The use of patient data in this study was approved by the University Health Network Research Ethics Board. The need to obtain patient consent was waived for this study because all information were gathered retrospectively and de-identified before reporting.

      Supplementary Material

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