Genetic Predisposition to Sarcoma: What Should Clinicians Know?

OPINION STATEMENT: Pathogenic germline variants in the setting of several associated cancer predisposition syndromes (CPS) may lead to the development of sarcoma. We would consider testing for a CPS in patients with a strong family history of cancer, multiple primary malignancies, and/or pediatric/adolescent/young adult patients diagnosed with other malignancies strongly associated with CPS. When a CPS is diagnosed in a patient with sarcoma, additional treatment considerations and imaging options for those patients are required. This applies particularly to the use of radiation therapy, ionizing radiation with diagnostic imaging, and the use of alkylating chemotherapy. As data and guidelines are currently lacking for many of these scenarios, we have adopted a shared decision-making process with patients and their families. If the best chance for cure in a patient with CPS requires utilization of radiation therapy or alkylating chemotherapy, we discuss the risks with the patient but do not omit these modalities. However, if there are treatment options that yield equivalent survival rates, yet avoid these modalities, we elect for those options. Considering staging imaging and post-therapy evaluation for sarcoma recurrence, we avoid surveillance techniques that utilize ionizing radiation when possible but do not completely omit them when their use is indicated.

Newborn Screening for Li-Fraumeni Syndrome: Patient Perspectives.

Background: Li-Fraumeni syndrome (LFS) is an inherited cancer predisposition syndrome with an estimated prevalence of 1 in 3,000-5,000 individuals. LFS poses a significant cancer risk throughout the lifespan, with notable cancer susceptibility in childhood. Despite being predominantly inherited, up to 20% of cases arise de novo. Surveillance protocols facilitate the reduction of mortality and morbidity through early cancer detection. While newborn screening (NBS) has proven effective in identifying newborns with rare genetic conditions, even those occurring as rarely as 1 in 185,000, its potential for detecting inherited cancer predispositions remains largely unexplored. Methods: This survey-based study investigates perspectives toward NBS for LFS among individuals with and parents of children with LFS receiving care at single comprehensive cancer center in the U.S. Results: All participants unanimously supported NBS for LFS (n = 24). Reasons included empowerment (83.3%), control (66.7%), and peace of mind (54.2%), albeit with concerns about anxiety (62.5%) and devastation (50%) related to receiving positive results. Participants endorsed NBS as beneficial for cancer detection and prevention (91.7%), research efforts (87.5%), and family planning (79.2%) but voiced apprehensions about the financial cost of cancer surveillance (62.5%), emotional burdens (62.5%), and insurance coverage and discrimination (54.2%). Approximately 83% of respondents believed that parental consent should be required to screen newborns for LFS. Conclusion: This study revealed strong support for NBS for LFS despite the recognition of various perceived benefits and risks. These findings underscore the complex interplay between clinical, psychosocial, and ethical factors in considering NBS for LFS from the perspective of the LFS community.

Severe congenital neutropenia, SRP54 pathogenicity, and a framework for surveillance.

Severe congenital neutropenia (SCN) is a rare disorder, often due to pathogenic variants in genes such as ELANE, HAX1, and SBDS. SRP54 pathogenic variants are associated with SCN and Shwachman-Diamond-like syndrome. Thirty-eight patients with SRP54-related SCN are reported in the literature. We present an infant with SCN, without classic Shwachman-Diamond syndrome features, who presented with recurrent bacterial infections and an SRP54 (c.349_351del) pathogenic variant. Despite ongoing granulocyte colony-stimulating factor therapy, this patient has no evidence of malignant transformation. Here we establish a framework for the future development of universal guidelines to care for this patient population.

BRCA1/2 Variants Identified Through Tumor Genomic Profiling: Assessing Genetic Counseling Outcomes.

PURPOSE: As tumor genomic profiling (TGP) is increasingly used to help guide cancer treatment, BRCA variants, which may or may not be reflective of the germline genome, are being identified. As TGP use increases, it is becoming an important tool for referral to genetic counseling and identifying patients with hereditary cancer syndromes such as hereditary breast and ovarian cancer. This study explores genetic counseling referral patterns and germline implications of patients found to have pathogenic BRCA1/2 variants identified through TGP. METHODS: Participants include patients at Huntsman Cancer Institute undergoing TGP through a single commercial laboratory between March 2014 and July 2018. A retrospective chart review was conducted for 62 patients found to have pathogenic variants (PVs) in BRCA1/2 on TGP. Data on genetic counseling referrals and uptake, germline test results, family history, and patient demographics were collected. RESULTS: In the study time frame, 1,899 patients underwent TGP. Testing identified 67 PVs in BRCA1 (23 variants) or BRCA2 (44 variants) in 62 patients. Thirty-five patients first received a referral to a genetic counselor following TGP with 33 patients completing genetic counseling. Of the 30 patients who pursued germline genetic testing following TGP, 11 were discovered to have a previously unknown germline BRCA PV. Nine of these patients were the first in their family diagnosed with hereditary breast and ovarian cancer. CONCLUSION: This study represents one institution's experience with genetic counseling referrals, uptake, and germline results following TGP. For some patients, TGP will be the first indicator of an underlying hereditary condition. Identifying patients with PVs (which may be germline) through TGP is an important new genetic counseling referral tool that can have important implications for the patient and their family.

The genetic landscape of germline DDX41 variants predisposing to myeloid neoplasms.

Germline DDX41 variants are the most common mutations predisposing to acute myeloid leukemia (AML)/myelodysplastic syndrome (MDS) in adults, but the causal variant (CV) landscape and clinical spectrum of hematologic malignancies (HMs) remain unexplored. Here, we analyzed the genomic profiles of 176 patients with HM carrying 82 distinct presumably germline DDX41 variants among a group of 9821 unrelated patients. Using our proposed DDX41-specific variant classification, we identified features distinguishing 116 patients with HM with CV from 60 patients with HM with variant of uncertain significance (VUS): an older age (median 69 years), male predominance (74% in CV vs 60% in VUS, P = .03), frequent concurrent somatic DDX41 variants (79% in CV vs 5% in VUS, P < .0001), a lower somatic mutation burden (1.4 ± 0.1 in CV vs 2.9 ± 0.04 in VUS, P = .012), near exclusion of canonical recurrent genetic abnormalities including mutations in NPM1, CEBPA, and FLT3 in AML, and favorable overall survival (OS) in patients with AML/MDS. This superior OS was determined independent of blast count, abnormal karyotypes, and concurrent variants, including TP53 in patients with AML/MDS, regardless of patient's sex, age, or specific germline CV, suggesting that germline DDX41 variants define a distinct clinical entity. Furthermore, unrelated patients with myeloproliferative neoplasm and B-cell lymphoma were linked by DDX41 CV, thus expanding the known disease spectrum. This study outlines the CV landscape, expands the phenotypic spectrum in unrelated DDX41-mutated patients, and underscores the urgent need for gene-specific diagnostic and clinical management guidelines.

Non-Melanoma Skin Cancers and Other Cutaneous Manifestations in Bone Marrow Failure Syndromes and Rare DNA Repair Disorders.

Although most non-melanoma skin cancers are felt to be sporadic in origin, these tumors do play a role in several cancer predisposition syndromes. The manifestations of skin cancers in these hereditary populations can include diagnosis at extremely early ages and/or multiple primary cancers, as well as tumors at less common sites. Awareness of baseline skin cancer risks for these individuals is important, particularly in the setting of treatments that may compromise the immune system and further increase risk of cutaneous malignancies. Additionally, diagnosis of these disorders and management of non-cutaneous manifestations of these diseases have profound implications for both the patient and their family. This review highlights the current literature on the diagnosis, features, and non-melanoma skin cancer risks associated with lesser-known cancer predisposition syndromes, including bone marrow failure disorders, genomic instability disorders, and base excision repair disorders.

Rare variant in the fumarate hydratase gene found in patients with clinical features of hereditary leiomyomatosis and renal cell cancer (HLRCC): A case series.

Hereditary leiomyomatosis and renal cell cancer (HLRCC) is an inherited cancer predisposition syndrome caused by autosomal dominant heterozygous pathogenic variants in the fumarate hydratase (FH) gene. FH pathogenic variant carriers are at an increased risk for cutaneous leiomyomas, renal cell cancer, and uterine fibroids. We present a case series of patients identified at two different medical institutions with clinically diagnostic features of HLRCC and a shared rare variant in the FH gene.

Inherited TP53 Variants and Risk of Prostate Cancer.

BACKGROUND: Inherited germline TP53 pathogenic and likely pathogenic variants (gTP53) cause autosomal dominant multicancer predisposition including Li-Fraumeni syndrome (LFS). However, there is no known association of prostate cancer with gTP53. OBJECTIVE: To determine whether gTP53 predisposes to prostate cancer. DESIGN, SETTING, AND PARTICIPANTS: This multi-institutional retrospective study characterizes prostate cancer incidence in a cohort of LFS males and gTP53 prevalence in a prostate cancer cohort. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: We evaluated the spectrum of gTP53 variants and clinical features associated with prostate cancer. RESULTS AND LIMITATIONS: We identified 31 prostate cancer cases among 163 adult LFS males, including 26 of 54 aged ≥50 yr. Among 117 LFS males without prostate cancer at the time of genetic testing, six were diagnosed with prostate cancer over a median (interquartile range [IQR]) of 3.0 (1.3-7.2) yr of follow-up, a 25-fold increased risk (95% confidence interval [CI] 9.2-55; p < 0.0001). We identified gTP53 in 38 of 6850 males (0.6%) in the prostate cancer cohort, a relative risk 9.1-fold higher than that of population controls (95% CI 6.2-14; p < 0.0001; gnomAD). We observed hotspots at the sites of attenuated variants not associated with classic LFS. Two-thirds of available gTP53 prostate tumors had somatic inactivation of the second TP53 allele. Among gTP53 prostate cancer cases in this study, the median age at diagnosis was 56 (IQR: 51-62) yr, 44% had Gleason ≥8 tumors, and 29% had advanced disease at diagnosis. CONCLUSIONS: Complementary analyses of prostate cancer incidence in LFS males and gTP53 prevalence in prostate cancer cohorts suggest that gTP53 predisposes to aggressive prostate cancer. Prostate cancer should be considered as part of LFS screening protocols and TP53 considered in germline prostate cancer susceptibility testing. PATIENT SUMMARY: Inherited pathogenic variants in the TP53 gene are likely to predispose men to aggressive prostate cancer.

AML with germline DDX41 variants is a clinicopathologically distinct entity with an indolent clinical course and favorable outcome.

Germline DDX41 variants in myeloid neoplasms (MNs) are not uncommon, and we explored the prevalence and characterized the clinical and pathologic features in a cohort of 3132 unrelated adult MN patients. By targeted next-generation sequencing, we identified 28 patients (20 men and 8 women) with pathogenic germline DDX41 variants who developed acute myeloid leukemia (AML), in which only 3 (11%) had a family history (FH) of MNs. A subacute clinical course of cytopenia (mean duration of 11.2 months, range 0-72 months) prior to the initial AML diagnosis was accompanied by a low blast count (median at 30%, range 20-70%) in hypocellular marrows (93% of all patients), in vast contrast to the typical proliferative subtypes of AML in the elderly. Most patients had a normal karyotype (75%) and acquired a second DDX41 variant (69%). A favorable overall survival (OS) was observed in comparison to that of common subtypes of AML with wild-type DDX41 in age-matched patients. Our study demonstrated that the frequent germline pathogenic DDX41 variants characterized a clinically distinct AML entity. Features characteristic of DDX41-mutated AML include male predominance, often lack of FH, indolent course, low proliferative potential, frequent somatic DDX41 variants, and a favorable OS.

"Being proactive, not reactive": exploring perceptions of genetic testing among White, Latinx, and Pacific Islander Populations.

Genetic testing is becoming an integral part of healthcare, but evidence suggests that both race and ethnicity influence access to and utilization of genetic testing. Given this barrier, data are needed on the perceptions of genetic testing in racial and ethnic minority groups. The purpose of this study was to explore the perceptions of three types of genetic testing (genetic testing for adult-onset conditions, prenatal screening, and newborn screening) in a sample of US participants who identified as White, Pacific Islander, and Latinx (10 dyads from each group for 60 participants total). Data were collected through semi-structured dyadic interviews and assessed using thematic analysis. The major themes were knowledge as empowering, knowledge as stressful, and predictive nature of prenatal testing and newborn screening. Some differences were seen in themes by race and ethnicity. A sense of collective and familial health appeared to be a more important theme for Pacific Islander and Latinx participants compared to White participants. Adult-onset genetic testing was viewed variously across all groups with some noting how it may increase anxiety, particularly if the disease screened for was unable to be prevented with action. All three groups reported on the positives of prenatal testing and newborn screening yet often were confused on the differences between them. This study presents novel perceptions of genetic testing in participants from diverse communities across three types of genetic testing. Genetic healthcare providers should incorporate participants' perceptions, values, and beliefs into their counseling delivery as a way to engage with diverse communities.

Two Clonally Distinct B-Cell Lymphomas Reveal the Diagnosis of XLP1 in a Male Child and His Asymptomatic Male Relatives: Case Report and Review of the Literature.

X-linked lymphoproliferative disease type 1 (XLP1) is a primary immunodeficiency disorder caused by pathogenic variants in the SH2D1A gene (SH2 domain containing protein 1A). Patients with XLP1 may present acutely with fulminant infectious mononucleosis, hemophagocytic lymphohistiocytosis, and/or B-cell non-Hodgkin lymphoma (B-NHL). We report a boy who developed 2 clonally distinct B-NHL 4 years apart and was found to have previously unrecognized XLP1. The report highlights the importance of clonal analysis and XLP1 testing in males with presumed late recurrences of B-NHL, and the role of allogeneic stem cell transplant (allo-SCT) in XLP1 patients and their affected male relatives.

Splicing profile by capture RNA-seq identifies pathogenic germline variants in tumor suppressor genes.

Germline variants in tumor suppressor genes (TSGs) can result in RNA mis-splicing and predisposition to cancer. However, identification of variants that impact splicing remains a challenge, contributing to a substantial proportion of patients with suspected hereditary cancer syndromes remaining without a molecular diagnosis. To address this, we used capture RNA-sequencing (RNA-seq) to generate a splicing profile of 18 TSGs (APC, ATM, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, MLH1, MSH2, MSH6, MUTYH, NF1, PALB2, PMS2, PTEN, RAD51C, RAD51D, and TP53) in 345 whole-blood samples from healthy donors. We subsequently demonstrated that this approach can detect mis-splicing by comparing splicing profiles from the control dataset to profiles generated from whole blood of individuals previously identified with pathogenic germline splicing variants in these genes. To assess the utility of our TSG splicing profile to prospectively identify pathogenic splicing variants, we performed concurrent capture DNA and RNA-seq in a cohort of 1000 patients with suspected hereditary cancer syndromes. This approach improved the diagnostic yield in this cohort, resulting in a 9.1% relative increase in the detection of pathogenic variants, demonstrating the utility of performing simultaneous DNA and RNA genetic testing in a clinical context.

Comparison of Somatic and Germline Variant Interpretation in Hereditary Cancer Genes.

PURPOSE: To compare the classification of genetic variants reported on tumor genomic profiling (TGP) reports with germline classifications on clinical test results and ClinVar. Results will help to inform germline testing discussions and decisions in patients with tumor variants in genes that are relevant to hereditary cancer risk. PATIENTS AND METHODS: This study compared somatic and germline classifications of small nucleotide variants in the following genes: BRCA1, BRCA2, CHEK2, PALB2, ATM, MLH1, MSH2, MSH6, and PMS2. Somatic classifications were taken from reports from a single commercial TGP laboratory of tests ordered by providers at Huntsman Cancer Institute between March 2014 and June 2018. Somatic variant interpretations were compared with classifications from germline test results as well as with ClinVar interpretations. RESULTS: Of the 623 variants identified on TGP, 353 had a definitive classification in ClinVar, and 103 were assayed with a germline test, with 66 of the variants tested observed in germline. Analysis of somatic variants of uncertain significance listed on TGP reports determined that 22% had a different interpretation compared with ClinVar and that 32% differed from the interpretation on a germline test result. Pathogenic variants on TGP test results were found to differ 13% and 5% of the time compared with ClinVar interpretations and germline test results, respectively. CONCLUSION: These results suggest that TGP variants are often classified differently in a germline context. Differences may be due to different processes in variant interpretation between somatic and germline laboratories. These results are important for health care providers to consider when making decisions about additional testing for hereditary cancer risks.

DNA Damage Repair (DDR) Mutations and the Utility of High-Risk Genetics Clinics in Metastatic Castration-Refractory Prostate Cancer (mCRPC).

Germline pathogenic variants (PVs) in DNA-repair genes have garnered increasing attention in metastatic prostate cancer, and more patients are having somatic and germline DNA testing performed. Interpretation of germline DNA testing is a novel challenge for many clinicians, and the results of germline DNA-repair gene testing have significant implications for men with advanced prostate cancer and their children and siblings. Here, we report the case of a man with metastatic castration-refractory prostate cancer and a pathogenic, germline BRCA2 variant. We discuss the significance of his referral to a high-risk genetics clinic and the unique targeted therapy that he responded to.