Search

PURPOSE: Testing for pathogenic variants can aid in oncologic risk stratification and identification of targeted therapies. Despite known disparities in access to prostate cancer (PCa) care, little has been written about access to germline genetic testing (GGT) for Black men and other historically marginalized populations. This systematic review sought to delineate racial/ethnic disparities in GGT for PCa. METHODS: This systematic review identified articles published from January 1996 through May 2021 in PubMed, Web of Science, and Embase. We included studies that reported rates of GGT in men with PCa in the United States by race/ethnicity as reflective of routine clinical care or research. A narrative synthesis was performed. RESULTS: Of 4,309 unique records, 91 studies examining 50 unique study populations met inclusion criteria. Of these, four populations included men who received GGT through routine clinical care, accounting for 4,415 men (72.6% White and 7.2% Black). The other 46 populations included men who received GGT as part of a research study, accounting for 30,824 men (64.3% White and 21.6% Black). Of these 46 research populations, 19 used targeted methods to increase recruitment from a specific demographic. CONCLUSION: Most studies that report GGT rates by race/ethnicity are in research settings. Many of these studies used targeted recruitment methods and subsequently have a greater proportion of Black men than clinical and US population–based studies. Other historically marginalized populations are not well represented. There remains a knowledge gap regarding the extent of racial disparities in the use of GGT, particularly in the clinical setting.

Purpose Herein, we report the frequency and distribution of germline pathogenic variants (PVs) among females with breast cancer (BC) and at least one other non-BC who underwent multi-gene panel testing (MGPT). Among females with PVs diagnosed first with BC or ovarian cancer (OC), we sought to enumerate the frequency of subsequent PV-associated cancers. Methods Females with BC and cancer of ≥ 1 other site (multiple primary cancers, MPC) who underwent MGPT through Ambry Genetics from March 2012 to December 2016 were included if they had testing of at least 21 genes of interest (ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, EPCAM, MLH1, MSH2, MSH6, MUTYH, NBN, NF1, PALB2, PMS2, PTEN, RAD51C, RAD51D, STK11, and TP53). Phenotypic data were abstracted from test requisition forms and clinical notes. Results Of 6,617 evaluable patients, most were White (70.8%) and median age at first cancer, second cancer, and MGPT was 49 (interquartile range [IQR]: 18), 59 (IQR: 16), and 63 (IQR: 16) years, respectively. PVs were found among 14.1% (932/6617) of the overall cohort and in 16.4% (440/2687) of females who were diagnosed first with BC. Among those, 55.2% (243/440) had an actionable PV associated with a subsequent cancer diagnosis including 150 OCs. Of the 2443 females with breast and ovarian cancer, few (n = 97, 9.5%) were diagnosed first with OC, limiting our analysis. Conclusions Females with MPC, including BC, have a high frequency of germline PVs (14.1%). These data delineate the opportunities for intercepting subsequent cancers associated with genetic risk among females diagnosed first with BC.

The familial aggregation of bladder cancers has been observed, but the incidence and association of familial bladder cancer with germline pathogenic and likely pathogenic (P/LP) variants is unknown.A retrospective analysis was conducted of patients with bladder cancer treated at the Dana-Farber Cancer Institute to identify those with a first-degree relative with bladder cancer. A second cohort of patients referred to DFCI for suspicion of a cancer predisposition syndrome was analyzed for candidate P/LP germline variants. Descriptive statistics were generated.Among 885 patients with bladder cancer, 38 patients (4.3%) had a family history of bladder cancer in a first-degree relative. No significant association of age of diagnosis was observed between patients with and without a first-degree family history of bladder cancer (P = .3). In the second cohort, 27 of 80 (34%) patients with bladder cancer evaluated for cancer predisposition syndromes harbored a P/LP germline variant. P/LP variants were identified most commonly in the following genes: BRCA1 (n = 5), MSH2 (n = 5), MLH1 (n = 4), ATM (n = 3), and CHEK2 (n = 2). Of the 27 patients with identified germline P/LP variants, 20 (74%) had a family history of a tumor component syndrome in a first- or second-degree relative and 3 were subsequently diagnosed with another genetically-linked associated cancer.Familial bladder cancer defined as bladder cancer in the proband and a first-degree relative, was present in 4.3% of patients with bladder cancer and was not associated with age of diagnosis. Additionally, among patients suspected to have a familial cancer syndrome, one-third harbored a germline P/LP variant. Further study of germline variants in patients with familial bladder cancer including somatic testing for loss of heterozygosity may provide insights regarding disease pathogenesis and inform therapy.

PURPOSE Guidelines recommend somatic and germline testing for men with advanced prostate cancer (PCa). Barriers to widespread implementation result in underutilization of germline testing. Somatic testing alone risks missing pathogenic germline variants (PGVs). We sought to determine whether the addition of germline testing to tumor-only sequencing improves detection of PGVs in men with advanced PCa. Secondarily, we sought to define the added value of combining somatic and germline testing to optimize detection of clinically actionable alterations. PATIENTS AND METHODS We analyzed results of independent germline testing and tumor-only sequencing from 100 men with advanced PCa from a prospective clinical trial (ClinicalTrials.gov identifier: NCT03328091 ). The primary outcome was the proportion of PGVs not reported with tumor-only sequencing. The secondary outcome was the association of locus-specific loss of heterozygosity for PGVs in homologous recombination genes with clinical-genomic features. RESULTS In the 100 men who underwent germline testing and tumor-only sequencing, 24 PGVs were identified, 17 of which were clinically actionable, in 23 patients. Tumor-only sequencing failed to report four (17%) of the PGVs. One additional PGV (4.2%) had variant allele frequency on tumor-sequencing below the threshold for follow-up germline testing. When integrating tumor-only sequencing with germling testing results, 33% of patients harbored clinically actionable alterations. Rates of locus-specific loss of heterozygosity were higher for BRCA2 PGVs in castration-resistant PCa than PGVs in other homologous recombination genes in hormone-sensitive PCa ( P = .029). CONCLUSION Tumor-only sequencing failed to report more than 20% of PGVs in men with advanced PCa. These findings strongly support guideline recommendations for universal germline and somatic testing in this population. Combining tumor and germline sequencing doubled the chance of detecting a clinically actionable alteration.

Background: Among females with breast cancer, multiple primary cancers (MPCs) are a hallmark of cancer predisposition syndromes. Herein we report the frequency of germline pathogenic/likely pathogenic variants (PVs) among females with breast cancer (BC) and primary cancer of >1 other site who underwent multi-gene panel testing (MGPT) through a single lab. Among females first diagnosed with BC who had a PV in an actionable gene, we quantified the frequency of subsequent breast and non-breast cancers. Among those who later developed a second BC, ovarian, endometrial or colon cancer, we determined the percentage of patients with MPCs who would have been identified as high-risk if all women had had MGPT after a first diagnosis of breast cancer. Methods: Females with breast cancer and MPCs who underwent germline genetic testing with Ambry Genetics from 3/2012 to 12/2016 were included in our cohort. Eligible individuals had multigene panel testing, which included 21 genes at minimum (ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, EPCAM, MLH1, MSH2, MSH6, MUTYH, NBN, NF1, PALB2, PMS2, PTEN, RAD51C, RAD51D, STK11, and TP53). Clinical factors including age at diagnosis, age at testing and cancer type were obtained from test requisition forms and clinical notes. Patients with >1 PV were excluded from the analysis. Results: Of the 6617 patients with MPCs including BC tested for the 21 genes in the analytic cohort, most were white (70.8%), with median age at testing 63 years (IQR: 16). The median ages of first and second cancer diagnosis were 49 (IQR: 18) and 59 (IQR: 16) years, respectively. Considering the diagnostic order of BC, PV prevalence was 16.5% (444/2687) with BC as the 1st cancer diagnosis, 11.2% (296/2641) with BC as the 2nd cancer diagnosis, 15.2% (49/323) as 3rd or later diagnosis (p Citation Format: Brittany L. Bychkovsky, Min-Tzu Lo, Amal Yussuf, Carrie Horton, Parichehr Hemyari, Holly LaDuca, Judy E. Garber, Huma Q. Rana. Pathogenic variants among female breast cancer patients with a subsequent cancer demonstrate preventable cancer burden [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P2-09-03.

Background and aims CDH1 germline variants have been linked to heritability in diffuse gastric (DGC) and lobular breast cancer (LBC). Studies have not yet assessed whether CDH1 is a cancer-susceptibility gene in other cancers. Herein, we mapped the landscape of pathogenic and likely pathogenic (P/LP) germline variants in CDH1 across various cancers and ethnicities. Methods We evaluated CDH1 germline P/LP variants in 212,944 patients at one CLIA-certified laboratory (Invitae) and described their frequency in 7 cancer types. We screened for CDH1 variant enrichment in each cancer relative to a cancer-free population from The Genome Aggregation Database version 3 (gnomADv3). Results CDH1 P/LP variants were identified in 141 patients, most commonly in patients with DGC (27/408, 6.6%) followed by colorectal signet-ring cell cancer (CSRCC; 3/79, 3.8%), gastric cancer (56/2756, 2%), and LBC (22/6809, 0.3%). CDH1 P/LP variants were enriched in specific ethnic populations with breast cancer, gastric cancer, CRC, LBC, DGC, and CSRCC compared to matched ethnicities from gnomADv3. Conclusion We report for the first time the prevalence of P/LP CDH1 variants across several cancers and show significant enrichment in CDH1 P/LP variants for patients with CSRCC, DGC, and LBC across various ethnicities. Future prospective studies are warranted to validate these findings.

Multiple primary cancers (MPCs) are a hallmark of cancer predisposition syndromes. Here the frequency of germline pathogenic variants (PVs) among patients with MPCs is reported.Patients with MPCs who underwent multigene panel testing from March 2012 to December 2016 were studied. Eligible patients had an analysis of 21 genes: ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, EPCAM, MLH1, MSH2, MSH6, MUTYH, NBN, NF1, PALB2, PMS2, PTEN, RAD51C, RAD51D, STK11, and TP53. The frequencies of PVs by sex, number of cancers, and age at diagnosis were compared with 2-sided χAmong the 9714 patients analyzed, most were female (91.1%) and White (71.0%); the median age at testing was 63 years, and the median ages at first and second cancer diagnoses were 49 and 58 years, respectively. Overall, 1320 (13.6%) had PVs. The prevalence of PVs increased with the number of primary cancers (PCs): 13.1% with 2 PCs, 15.9% with 3 PCs, and 18.0% with ≥4 PCs (P = .00056). Differences in the prevalence of PVs by age at diagnosis were significant: 14.7% with 2 PCs at an age50 years, 15.8% with 1 PC at an age50 years, and 12.0% with all PCs at an age ≥ 50 years (P = 2.07E-05). PVs by the age at second cancer diagnosis were also significant: 14.7% at an age50 years, 13.9% at an age of 50 to 69 years, and 11.4% at an age ≥ 70 years (P for trend = .005).Among patients with MPCs, there is a high frequency of germline PVs, with a higher frequency found among patients with a higher number of PCs. These findings suggest that genetic testing should be considered even among patients who are older at the diagnosis of an additional primary malignancy.

PURPOSE Multigene panel testing (MGPT) identifies TP53 pathogenic or likely pathogenic (P/LP) variants in patients with diverse phenotypes, of which only one is classic Li-Fraumeni syndrome. Low variant allelic fraction (VAF) in TP53 found on germline testing may suggest aberrant clonal expansion or constitutional mosaicism. We evaluated TP53-positive probands seen in a cancer genetics program to determine germline versus somatic status. METHODS We reviewed TP53-positive probands from 2012 to 2019 identified by MGPT on blood or saliva (N = 84). Available VAFs were collected. Probands with a familial variant, who met Li-Fraumeni syndrome testing criteria or who carried a founder variant, were considered germline. For those with uncertain germline status, TP53 variants were further examined using ancillary data of family members and somatic tissue. RESULTS Of the 84 probands, 54.7% had germline variants with 33.3% meeting criteria for germline status and 21.4% confirmed through ancillary testing. Aberrant clonal expansion comprised 13.1% with clonal hematopoiesis of indeterminate potential and 2.4% with a hematologic malignancy. Constitutional mosaicism was confirmed in 8.3% probands. Definitive status could not be determined in 3.6% despite ancillary assessment, and 17.9% did not have ancillary testing. CONCLUSION A TP53 P/LP variant found on peripheral blood or saliva MGPT does not always originate in the germline. In a clinical cancer genetics cohort, approximately half of the patients had TP53 P/LP germline variants; these patients plus those with constitutional mosaicism require intensified surveillance. A framework of multiple strategies enables discernment of germline from constitutional mosaic and acquired variants, which is essential for appropriate management.

Concurrent pathogenic variants (PVs) in cancer predisposition genes have been reported in 0.1-2% of hereditary cancer (HC) patients. Determining concurrent PVs is crucial for the diagnosis, treatment, and risk assessment of unaffected family members. Next generation sequencing based diagnostic tests, which are widely used in HCs, enable the evaluation of multiple genes in parallel. We have screened the family members of a patient with bilateral breast cancer who was found to have concurrent PVs in BRCA1 (NM_007294.3;c.5102_5103del, p.Leu1701Glnfs*14) and MUTYH (NM_001128425.1;c.884CT, p.Pro295Leu). Further analysis revealed concurrent PVs in CHEK2 (NM_007194.4;c.1427CT, p.Thr476Met) and MUTYH (NM_001128425.1;c.884CT, p.Pro295Leu) in the maternal uncle of the index case. Eight additional family members were found to have PVs in BRCA1 and MUTYH among 26 tested relatives. The sister and the brother of the index case who were diagnosed with breast and colon cancers, respectively, presented with the same genotype as the index case. Each family member was evaluated individually for clinical care and surveillance. This is the first report describing a family with BRCA1, MUTYH and CHEK2 concurrent PVs. Our findings provide valuable information for the assessment and management considerations for families with concurrent PVs.

Multigene panel testing (MGPT) identifiesWe reviewedOf the 84 probands, 54.7% had germline variants with 33.3% meeting criteria for germline status and 21.4% confirmed through ancillary testing. Aberrant clonal expansion comprised 13.1% with clonal hematopoiesis of indeterminate potential and 2.4% with a hematologic malignancy. Constitutional mosaicism was confirmed in 8.3% probands. Definitive status could not be determined in 3.6% despite ancillary assessment, and 17.9% did not have ancillary testing.A

PURPOSE Whether individuals with monoallelic FH pathogenic variants (PVs) associated with autosomal recessive fumarate hydratase (FH) deficiency are also at risk of autosomal dominant FH-associated tumors is of paramount clinical importance. METHODS A retrospective study of individuals with a PV in the FH gene identified via multigene panel testing from 2012 to 2019 through a single testing laboratory was performed. Cancer histories of individuals with PVs in FH ( FH PV) were compared to those with PVs associated only with autosomal recessive FH deficiency (FH-d PV) and to FH-negative controls. Cancer histories of individuals with truncating versus nontruncating FH PV were also compared. RESULTS Individuals with FH PV were more likely to have kidney cancer than those with FH-d PV (odds ratio, 9.0; 95% CI, 4.4 to 20.0; P < .001) or FH-negative controls (odds ratio, 7.6; 95% CI, 5.2 to 11.2; P value < .001). The FH PV cohort had kidney cancer at a significantly younger age (median age: 35.0 years; interquartile range, 26.0-45.0 years) than the FH-d PV cohort (median age: 44.5 years; interquartile range, 43.5-53.5 years; P = .011). Within the FH PV cohort, there were no differences in the frequency or age at kidney cancer between those with truncating versus nontruncating PV. CONCLUSION Unlike FH PV, FH-d PV are not associated with kidney cancers at early ages of onset. The FH-d PV cohort had a cancer phenotype that resembled FH-negative controls. These data may inform genetic counseling and risk assessment of individuals with FH-d PV.

Background: Cancer family history is a vital part of cancer genetic counseling (GC) and genetic testing (GT), but increasing indications for germline cancer GT necessitate less labor-intensive models of collection. We evaluated the impact of GC on patient pedigrees generated by an electronic cancer family history questionnaire (eCFHQ). Methods: An Institutional Review Board–approved review of pedigrees collected through an eCFHQ was conducted. Paired pre-GC and post-GC pedigrees (n=1,113 each group) were analyzed independently by cancer genetic counselors for changes in patient-reported clinical history and to determine whether the pedigrees met NCCN GT criteria. Discrepancy in meeting NCCN GT criteria between pre-GC and post-GC pedigrees was the outcome variable of logistic regressions, with patient and family history characteristics as covariates. Results: Overall, 780 (70%) patients had cancer (affected), 869 (78%) were female, and the median age was 57 years (interquartile range, 45–66 years; range, 21–91 years). Of the 1,113 pairs of pre-GC and post-GC pedigrees analyzed, 85 (8%) were blank, 933 (84%) were not discrepant, and 95 (9%) were discrepant in meeting any NCCN GT criteria. Of the discrepant pedigrees, n=79 (83%) became eligible for testing by at least one of the NCCN GT criteria after GC. Patients with discrepant pedigrees were more likely to report no or unknown history of GT (odds ratio [OR], 4.54; 95% CI, 1.66–18.70; P=.01, and OR, 18.47; 95% CI, 5.04–88.73; PP=.02). Conclusions: For most patients (84%), a standalone eCFHQ was sufficient to determine whether NCCN GT criteria were met. More research is needed on the performance of the eCFHQ in diverse patient populations.

ImportanceGermline CHEK2 pathogenic variants (PVs) are frequently detected by multigene cancer panel testing (MGPT), but our understanding of PVs beyond c.1100del has been limited.ObjectiveTo compare cancer phenotypes of frequent CHEK2 PVs individually and collectively by variant type.Design, Setting, and ParticipantsThis retrospective cohort study was carried out in a single diagnostic testing laboratory from 2012 to 2019. Overall, 3783 participants with CHEK2 PVs identified via MGPT were included. Medical histories of cancer in participants with frequent PVs, negative MGPT (wild type), loss-of-function (LOF), and missense were compared.Main Outcomes and MeasuresParticipants were stratified by CHEK2 PV type. Descriptive statistics were summarized including median (IQR) for continuous variables and proportions for categorical characteristics. Differences in age and proportions were assessed with Wilcoxon rank sum and Fisher exact tests, respectively. Frequencies, odds ratios (ORs), 95% confidence intervals were calculated, and P values were corrected for multiple comparisons where appropriate.ResultsOf the 3783 participants with CHEK2 PVs, 3473 (92%) were female and most reported White race. Breast cancer was less frequent in participants with p.I157T (OR, 0.66; 95% CI, 0.56-0.78; PPP = .04) PVs compared with other PVs and an association with nonbreast cancers was not found. Following the exclusion of p.I157T, p.S428F, and p.T476M, participants with monoallelic CHEK2 PV had a younger age at first cancer diagnosis (P P P P CHEK2 PV were less likely to have a diagnosis of colorectal cancer (OR, 0.62; 95% CI, 0.51-0.76; P CHEK2 PVs and c.1100del and no differences between CHEK2 missense and LOF PVs.Conclusions and RelevanceCHEK2 PVs, with few exceptions (p.I157T, p.S428F, and p.T476M), were associated with similar cancer phenotypes irrespective of variant type. CHEK2 PVs were not associated with colorectal cancer, but were associated with breast, kidney, and thyroid cancers. Compared with other CHEK2 PVs, the frequent p.I157T, p.S428F, and p.T476M alleles have an attenuated association with breast cancer and were not associated with nonbreast cancers. These data may inform the genetic counseling and care of individuals with CHEK2 PVs.

BACKGROUND: Inflammation and one of its mediators, NF-kappa B (NFκB), have been implicated in prostate cancer carcinogenesis. We assessed whether germline polymorphisms associated with NFκB are associated with the risk of developing lethal disease (metastases or death from prostate cancer).METHODS: Using a Bayesian approach leveraging NFκB biology with integration of publicly available datasets we used a previously defined genome-wide functional association network specific to NFκB and lethal prostate cancer. A dense-module-searching method identified modules enriched with significant genes from a genome-wide association study (GWAS) study in a discovery data set, Physicians' Health Study and Health Professionals Follow-up Study (PHS/HPFS). The top 48 candidate single nucleotide polymorphisms (SNPs) from the dense-module-searching method were then assessed in an independent prostate cancer cohort and the one SNP reproducibly associated with lethality was tested in a third cohort. Logistic regression models evaluated the association between each SNP and lethal prostate cancer. The candidate SNP was assessed for association with lethal prostate cancer in 6 of 28 studies in the prostate cancer association group to investigate cancer associated alterations in the genome (PRACTICAL) Consortium where there was some medical record review for death ascertainment which also had SNP data from the ONCOARRAY platform. All men self-identified as Caucasian.RESULTS: The rs1910301 SNP which was reproducibly associated with lethal disease was nominally associated with lethal disease (odds ratio [OR] = 1.40; p = .02) in the discovery cohort and the minor allele was also associated with lethal disease in two independent cohorts (OR = 1.35; p = .04 and OR = 1.35; p = .07). Fixed effects meta-analysis of all three cohorts found an association: OR = 1.37 (95% confidence interval [CI]: 1.15-1.62, p = .0003). This SNP is in the promoter region of FRAS1, a gene involved in epidermal-basement membrane adhesion and is present at a higher frequency in men with African ancestry. No association was found in the subset of studies from the PRACTICAL consortium studies which had a total of 106 deaths out total of 3263 patients and a median follow-up of 4.4 years.CONCLUSIONS: Through its connection with the NFκB pathway, a candidate SNP with a higher frequency in men of African ancestry without cancer was found to be associated with lethal prostate cancer across three well-annotated independent cohorts of Caucasian men.

Purpose To date, there has not been a large, systematic evaluation of the prevalence of germline risk variants in urothelial carcinoma (UC). Methods We evaluated the frequency of germline pathogenic and likely pathogenic variants in 1038 patients with high-risk UC who underwent targeted clinical germline testing. Case–control enrichment analysis was performed to screen for pathogenic variant enrichment in 17 DNA repair genes in 1038 UC patients relative to cancer-free individuals. Results Among 1038 patients with UC, the cumulative frequency of patients with pathogenic variants was 24%; 18.6% of patients harbored ≥1 actionable germline variant with preventive or therapeutic utility. MSH2 (34/969, 3.5%) and BRCA1/2 (38/867, 4.4%) germline variants had the highest frequency. Germline variants in DNA damage repair genes accounted for 78% of pathogenic germline variants. Compared to the cancer-free cohort, UC patients had significant variant enrichment in MSH2 (odds ratio [OR]: 15.4, 95% confidence interval [CI]: 7.1–32.7, p

Panel testing has led to the identification of TP53 pathogenic/likely pathogenic (P/LP) variant carriers (TP53+) who exhibit a broad range of phenotypes. We sought to evaluate and compare genotype–phenotype associations among TP53+ panel-ascertained subjects. Between 2012 and 2017, 317 TP53+ subjects (279 females and 38 males) identified through panel testing at one testing laboratory were found to have evaluable clinical histories and molecular results. Subject cancer histories were obtained from test requisition forms. P/LP variants were categorized by type and were examined in relation to phenotype. Loss-of-function (LOF) variants were associated with the earliest age at first cancer, with a median age of 30.5 years (P = 0.014); increased frequency of a sarcoma diagnosis (P = 0.016); and more often meeting classic LFS testing and Chompret 2015 criteria (P = 0.004 and 0.002 respectively), as compared with dominant-negative missense, other missense, or miscellaneous (splice or in-frame deletion) P/LP variant categories. Loss-of-function variants were more often associated with characteristic LFS cancer histories than other variant categories in TP53+ carriers ascertained through multigene panel testing. These findings require validation in other TP53+ cohorts. Genetic counseling for panel-ascertainedTP53+ individuals should reflect the dynamic expansion of the Li–Fraumeni syndrome phenotype.

Vulvar melanoma is a rare and aggressive cancer with a poor prognosis. The etiology of mucosal melanoma remains largely uncharacterized and no hereditary risk factors are established for this rare disease. While the germline variant MITF p.E318K confers an increased risk for cutaneous melanoma, this variant has not been associated with risk of non-cutaneous melanoma. Herein, we describe the presence of a germline MITF p.E318K pathogenic variant in a 47-year-old woman with vulvar melanoma and a family history of cutaneous melanoma in a first-degree relative. To our knowledge, this is the first reported case of MITF p.E318K in vulvar melanoma. This finding highlights the potential involvement of MITF p.E318K in risk assessment and clinical management of patients with vulvar melanoma. Further study of this observation is needed to inform appropriate identification of patients with non-cutaneous melanoma for MITF germline genomic evaluation and to potentially guide management for early detection of vulvar melanoma.

Summary: Prior studies of the renal cell carcinoma (RCC) germline landscape investigated predominantly patients of European ancestry. We examine the frequency of germline pathogenic and likely pathogenic (P/LP) variants in 1,829 patients with RCC from various ancestries. Overall, P/LP variants are found in 17% of patients, among whom 10.3% harbor one or more clinically actionable variants with potential preventive or therapeutic utility. Patients of African ancestry with RCC harbor significantly more P/LP variants in FH compared to patients of non-African ancestry with RCC and African controls from the Genome Aggregation Database (gnomAD). Patients of non-African ancestry have significantly more P/LP variants in CHEK2 compared to patients of African ancestry with RCC and non-Finnish Europeans controls. Non-Africans with RCC have more actionable variants compared to Africans with RCC. This work helps understand the underlying biological differences in RCC between Africans and non-Africans and paves the way to more comprehensive genomic characterization of underrepresented populations.

Germline pathogenic TERT variants are associated with short telomeres and an increased risk of developing myelodysplastic syndrome (MDS) among patients with a telomere biology disorder. We identified TERT rare variants in 41 of 1514 MDS patients (2.7%) without a clinical diagnosis of telomere biology disorder who underwent allogeneic transplantation. Patients with TERT rare variants had shorter telomere length (pTERT rare variant. In multivariable analyses, TERT rare variants were associated with inferior overall survival (p=0.034) driven by an increased incidence of non-relapse mortality (NRM) (p=0.015). Death from a non-infectious pulmonary cause was more frequent among patients with a TERT rare variant. According to ACMG/AMP guidelines and Sherloc criteria, 39 TERT rare variants were classified as VUS and one as likely pathogenic. Therefore, we cloned all rare missense variants and quantified their impact on telomere elongation in a cell-based assay. We found that 36 of 40 variants had severe or intermediate impairment in their capacity to elongate telomeres. Using a homology model of human TERT bound to the shelterin protein TPP1, we inferred that TERT rare variants disrupt domain-specific functions, including catalysis, protein-RNA interactions, and recruitment to telomeres. Our results indicate that the contribution of TERT rare variants to MDS pathogenesis and NRM risk is underrecognized and routine screening for TERT rare variants in MDS patients regardless of age or clinical suspicion could identify clinically inapparent telomere biology disorders and improve transplant outcomes through risk-adapted approaches.

10514 Background: Germline multigene panel testing has led to the increased detection of multiple co-occurring pathogenic variants (PV) in the same individual. As this occurrence is still relatively rare, reports of these individuals have been limited. Therefore, we sought to describe the clinical features of individuals with multiple PV identified at a single high-volume diagnostic laboratory. Methods: We performed a retrospective review of demographics and clinical data for individuals with > 1 pathogenic or likely pathogenic variant (PV) who underwent hereditary cancer panel testing (5-67 genes) between May 2012 and April 2017. In recessive genes (i.e. MUTYH), PV were only included when biallelic. PVs with reduced penetrance ( APC p.I1307K; CHEK2 p.I157T, p.S428F, p.T476M) were excluded. In individuals with the most common combinations of genes, personal cancer history and age at cancer diagnosis was evaluated. Results: A total of 555 individuals were identified with multiple PVs. Most individuals were female (85.1%), had a personal history of cancer (73.3%) and 26.3% had two or more primary cancers. CHEK2 was most often seen in co-occurrence with a PV in a different gene (137 observations), followed by ATM (120 observations), BRCA2 (110 observations), and BRCA1 (88 observations). Among cases in which clinical information was provided (n = 545), the five most frequent co-occurring combinations were in ATM/CHEK2 (25), ATM/BRCA2 (23), BRCA1/CHEK2 (19), CHEK2/CHEK2 (16), and BRCA2/CHEK2 (14). Individuals with co-occurring PVs in CHEK2/CHEK2 had the youngest age at first cancer diagnosis (mean = 41.5y; median = 42y), the highest rate of breast cancer diagnoses and other cancer diagnoses (100.0% and 70.6% of individuals, respectively), and the highest proportion of individuals with > 1 primary cancer (52.9%). Conclusions: Our results indicate that individuals with two PVs in CHEK2 have an average age of cancer onset that is similar to individuals with either a BRCA1 or BRCA2 concurrent PV. Additionally, individuals with two PVs in CHEK2 were more likely to have multiple primary cancers as compared to others in the cohort with concurrent PVs including those with either a BRCA1 or BRCA2 concurrent PV (Table). Continued studies, including comparisons to individuals with one PV, will provide valuable insight to aid in counseling and management of individuals with multiple germline PV. [Table: see text]

Patient: Female, 62-year-old Final Diagnosis: Medullary thyroid microcarcinoma Symptoms: No pain or swelling in her neck • no dysphagia or odynophagia • no changes in voice Medication: — Clinical Procedure: Genetic analysis Specialty: Genetics Objective: Unusual clinical course Background: RET p.V804M is a known activating oncogenic variant that confers an increased risk for medullary thyroid carcinoma (MTC). Based on age-specific penetrance, the American Thyroid Association (ATA) categorizes this variant as posing moderate risk. Therefore, ATA guidelines endorse prophylactic thyroidectomy for carriers in childhood (by age 5–10 years) or adulthood, or when the serum calcitonin level becomes elevated. The recommendation for thyroidectomy is increasingly controversial due to the recently reported low penetrance of the RET p.V804M variant in a large unbiased ascertainment cohort. Case Report: We describe the unexpected identification of this variant in a 62-year-old woman undergoing broad, multigene cancer panel testing for her personal and family history of breast cancer. There was no known family history of MTC. Biochemical screening prompted by the RET p.V804M result revealed a mildly elevated serum calcitonin. Pathology examination of her thyroidectomy specimen revealed multifocal medullary thyroid microcarcinoma; her sibling’s prophylactic thyroidectomy after a RET p.V840M-positive result similarly revealed early-stage MTC. Conclusions: This report demonstrates the value of genetic counseling, shared decision-making, cascade testing, and timely thyroidectomy in the management of a patient with an unexpected RET p.V804M result.

Objective Germline genetic testing is crucial to the care of ovarian cancer patients, and as part of the guideline-based care for ovarian cancer patient's adherence to this recommendation has been low. We sought to determine whether embedding a genetic counselor (GC) within a medical and gynecologic oncology clinic would increase testing rates and improve the timeliness of testing. Methods Prospective cohort study of 358 ovarian cancer patients seen by medical and gynecologic oncologists between 2013 and 2015. Rates of referrals, completion of counseling, and genetic testing and timeliness of counseling were abstracted before and after a GC was embedded in the clinic in 2014. An additional year of data (2015) was collected to evaluate sustainability of the intervention. Results Between 2013 and 2015, 88–92% of women were referred for genetic testing, but in 2013 only 66% completed counseling and 61% were tested. After a GC was embedded in the clinic in 2014, more than 80% of referred women completed counseling and germline genetic testing. Time to genetic counseling also decreased from a median of 107 to 40 days, irrespective of age and cancer family history (p Conclusions Embedding a GC into the workflow for ovarian cancer patients is an effective way of improving access to genetic counseling, testing rates, and the timeliness of testing.

Prior studies of the germline landscape of renal cell carcinoma (RCC) have centered around predominantly white patients of European ancestry. We examined the frequency of germline pathogenic and likely pathogenic (P/LP) variants in 1,829 patients with RCC from various ancestries. Overall, P/LP variants were found in 17%, among which 10.3% harbored ≥1 clinically actionable germline variant with potential preventive or therapeutic utility. Patients with African ancestry harbored significantly more P/LP variants in FH compared to patients of European ancestry. Patients with European ancestry had significantly more P/LP variants in CHEK2 and overall had more actionable variants compared to patients with African ancestry. This work helps better understand the underlying biological differences in RCC between Africans and Europeans. In addition, this work may pave the way to a much more comprehensive and global genomic characterization of underrepresented populations.

Background Li-Fraumeni syndrome (LFS) has traditionally been identified by single-gene testing (SGT) of TP53 triggered by clinical criteria, but the widespread use of multigene panel tests (MGPTs) has upended this paradigm. We sought to compare the personal and family cancer histories of TP53-positive result (TP53+) carriers who were identified by either MGPT or SGT. Methods Of 44 310 individuals who underwent testing of TP53 in a single clinical diagnostic laboratory between 2010 and 2014, 44 086 (40 885 MGPT and 3201 SGT) met study eligibility criteria. Personal cancer histories were available for 38 938 subjects. The frequency of germline TP53 results and various phenotypic manifestations were compared according to test type. All statistical tests were two-sided. Results MGPT TP53+ individuals (n = 126) had an older median age at first cancer than SGT TP53+ carriers (n = 96; women: median = 36 vs 28 years, P < .001; and men: median = 40 vs 15 years, P = .004). The median age of breast cancer diagnosis was 40 years in MGPT TP53+ women vs 33 years in SGT TP53+ women (P < .001). In both cohorts, childhood and LFS core cancers, and for women, multiple primary cancers (not multiple breast tumors), were associated with TP53+ results. Established LFS testing criteria were less often met by MGPT TP53+ individuals. Conclusions MGPT TP53+ individuals differ in phenotype from those ascertained through SGT and are notably older at cancer diagnosis and less likely to meet LFS clinical criteria. These findings suggest that LFS may have a greater phenotypic spectrum than previously appreciated. This has implications for the counseling of MGPT TP53+ individuals. Prospective follow-up of these individuals and families is needed to re-evaluate cancer risks.

Von Hippel-Lindau (VHL) syndrome is a hereditary cancer genetic condition associated with inactivating pathogenic alterations in the VHL tumor suppressor gene located at 3p (short arm of chromosome 3). Classic features of VHL include clear cell renal cell carcinoma, hemangioblastomas of the brain, spinal cord, and retina, pheochromocytoma, pancreatic cysts, and neuroendocrine tumors. Two sets of genomic information may be available from patients with VHL: the germline data showing the constitutional genetic profile and somatic profile obtained from patient tumor(s). Here we present both somatic and germline dataset from heterozygous carriers of germline VHL variants who exhibit non-syndromic VHL phenotypes. This data description article accompanies the paper “Pathogenicity of VHL variants in families with non-syndromic von Hippel-Lindau phenotypes: an integrated evaluation of germline and somatic genomic results by Huma Q. Rana, Diane R. Koeller, Alison Schwartz, Danielle K. Manning, Katherine A. Schneider, Katherine M. Krajewski, Toni K. Choueiri, Neal I. Lindeman, Judy E. Garber, Arezou A. Ghazani. We provide next generation sequencing (NGS) data obtained from DNA from tumors (renal cancer, bladder cancer, and cerebral hemangioblastoma) of three VHL carriers. The somatic dataset was analyzed for single nucleotide variants (SNVs) and copy number variants (CNVs) in 447 cancer genes, and structural variation (SVs) in 191 regions across 60 genes for rearrangements. We also present germline raw NGS data and analyzed SNV and CNV data in exonic regions of 133 hereditary cancer genes obtained from the peripheral blood of two VHL carriers.

Implementing cancer precision medicine in the clinic requires assessing the therapeutic relevance of genomic alterations. A main challenge is the systematic interpretation of whole-exome sequencing (WES) data for clinical care. One hundred sixty-five adults with metastatic colorectal and lung adenocarcinomas were prospectively enrolled in the CanSeq study. WES was performed on DNA extracted from formalin-fixed paraffin-embedded tumor biopsy samples and matched blood samples. Somatic and germ-line alterations were ranked according to therapeutic or clinical relevance. Results were interpreted using an integrated somatic and germ-line framework and returned in accordance with patient preferences. At the time of this analysis, WES had been performed and results returned to the clinical team for 165 participants. Of 768 curated somatic alterations, only 31% were associated with clinical evidence and 69% with preclinical or inferential evidence. Of 806 curated germ-line variants, 5% were clinically relevant and 56% were classified as variants of unknown significance. The variant review and decision-making processes were effective when the process was changed from that of a Molecular Tumor Board to a protocol-based approach. The development of novel interpretive and decision-support tools that draw from scientific and clinical evidence will be crucial for the success of cancer precision medicine in WES studies. Genet Med advance online publication 26 January 2017

Purpose Significant concerns exist regarding the potential for unwarranted behavior changes and the overuse of health care resources in response to direct-to-consumer personal genomic testing (PGT). However, little is known about customers’ behaviors after PGT. Methods Longitudinal surveys were given to new customers of 23andMe (Mountain View, CA) and Pathway Genomics (San Diego, CA). Survey data were linked to individual-level PGT results through a secure data transfer process. Results Of the 1,042 customers who completed baseline and 6-month surveys (response rate, 71.2%), 762 had complete cancer-related data and were analyzed. Most customers reported that learning about their genetic risk of cancers was a motivation for testing (colorectal, 88%; prostate, 95%; breast, 94%). No customers tested positive for pathogenic mutations in highly penetrant cancer susceptibility genes. A minority of individuals received elevated single nucleotide polymorphism-based PGT cancer risk estimates (colorectal, 24%; prostate, 24%; breast, 12%). At 6 months, customers who received elevated PGT cancer risk estimates were not significantly more likely to change their diet, exercise, or advanced planning behaviors or engage in cancer screening, compared with individuals at average or reduced risk. Men who received elevated PGT prostate cancer risk estimates changed their vitamin and supplement use more than those at average or reduced risk (22% v 7.6%, respectively; adjusted odds ratio, 3.41; 95% CI, 1.44 to 8.18). Predictors of 6-month behavior include baseline behavior (exercise, vitamin or supplement use, and screening), worse health status (diet and vitamin or supplement use), and older age (advanced planning, screening). Conclusion Most adults receiving elevated direct-to-consumer PGT single nucleotide polymorphism-based cancer risk estimates did not significantly change their diet, exercise, advanced care planning, or cancer screening behaviors.

Paraganglioma, HIF-2α, and Cyanotic Heart Disease Four of five patients with paragangliomas and pheochromocytomas who had received a diagnosis of congenital cyanotic heart disease had mutant HIF-2α. This contrasts with the prevalence of mutant HIF-2 in these tumor types in the absence of cyanotic heart disease (6 to 10%).

Importance Performing DNA genetic testing (DGT) for hereditary cancer genes is now a well-accepted clinical practice; however, the interpretation of DNA variation remains a challenge for laboratories and clinicians. Adding RNA genetic testing (RGT) enhances DGT by clarifying the clinical actionability of hereditary cancer gene variants, thus improving clinicians’ ability to accurately apply strategies for cancer risk reduction and treatment. Objective To evaluate whether RGT is associated with improvement in the diagnostic outcome of DGT and in the delivery of personalized cancer risk management for patients with hereditary cancer predisposition. Design, Setting, and Participants Diagnostic study in which patients and/or families with inconclusive variants detected by DGT in genes associated with hereditary breast and ovarian cancer, Lynch syndrome, and hereditary diffuse gastric cancer sent blood samples for RGT from March 2016 to April 2018. Clinicians who ordered genetic testing and received a reclassification report for these variants were surveyed to assess whether RGT-related variant reclassifications changed clinical management of these patients. To quantify the potential number of tested individuals who could benefit from RGT, a cohort of 307 812 patients who underwent DGT for hereditary cancer were separately queried to identify variants predicted to affect splicing. Data analysis was conducted from March 2016 and September 2018. Main Outcomes and Measures Variant reclassification outcomes following RGT, clinical management changes associated with RGT-related variant reclassifications, and the proportion of patients who would likely be affected by a concurrent DGT and RGT multigene panel testing approach. Results In total, 93 if 909 eligible families (10.2%) submitted samples for RGT. Evidence from RGT clarified the interpretation of 49 of 56 inconclusive cases (88%) studied; 26 (47%) were reclassified as clinically actionable and 23 (41%) were clarified as benign. Variant reclassifications based on RGT results changed clinical management recommendations for 8 of 18 patients (44%) and 14 of 18 families (78%), based on responses from 18 of 45 clinicians (40%) surveyed. A total of 7265 of 307 812 patients who underwent DGT had likely pathogenic variants or variants of uncertain significance potentially affecting splicing, indicating that approximately 1 in 43 individuals could benefit from RGT. Conclusions and Relevance In this diagnostic study, conducting RNA testing resolved a substantial proportion of variants of uncertain significance in a cohort of individuals previously tested for cancer predisposition by DGT. Performing RGT might change the diagnostic outcome of at least 1 in 43 patients if performed in all individuals undergoing genetic evaluation for hereditary cancer.

Background Inflammatory breast cancer (IBC) is an uncommon and aggressive subtype of breast cancer associated with early disease recurrence and short survival. The prevalence of germline variants in cancer predisposition genes has not been systematically evaluated in women with IBC. Methods Among 301 women enrolled in the clinical IBC registry at a single institution between 2010 and 2017, 168 had documented genetic testing. A second cohort of 200 IBC cases who had panel-based germline testing performed through a commercial testing laboratory from 2012 to 2017 was added to the analyses. Personal and family cancer histories and genetic testing results were evaluated when they were available for both cohorts. Results Among 501 IBC cases, 368 had documented genetic testing. Germline mutations (56 total) were identified in 53 cases (14.4%). BRCA1 or BRCA2 mutations were found in 7.3% of the subjects, 6.3% had a mutation in other breast cancer genes (PALB2, CHEK2, ATM, and BARD1), and 1.6% had mutations in genes not associated with breast cancer. The prevalence of mutations was 24% (22 of 92) among women with triple-negative IBC, 13% (13 of 99) among women with estrogen receptor- and/or progesterone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative disease, and 9.3% (10 of 108) among women with HER2-positive IBC. Conclusions The prevalence and diversity of germline genetic mutations among patients with IBC suggest that further studies should be performed to assess the role of inherited mutations in IBC carcinogenesis in comparison with non-IBC breast cancer. Since IBC has a high metastatic potential associated with poor prognostic outcomes, proposed future studies may also inform targeted treatment options.

10595 Background: Multiple primary cancers (MPCs) are a hallmark of cancer predisposition syndromes. We aim to characterize the frequency of germline pathogenic/likely pathogenic variants (PVs) among patients with MPCs. Herein we report the frequency of PVs by sex, number of cancers and age at diagnosis among a laboratory-based cohort of patients with MPCs. Methods: Patients with MPCs who underwent germline genetic testing with Ambry Genetics from 3/2012 to 12/2016 were included in our cohort. Eligible individuals had multigene panel testing, which included 21 genes, at minimum: ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, EPCAM, MLH1, MSH2, MSH6, MUTYH, NBN, NF1, PALB2, PMS2, PTEN, RAD51C, RAD51D, STK11, and TP53. Clinical factors including age at diagnosis, age at testing and cancer type were obtained from test requisition forms and clinical notes. Patients with > 1 PVs were excluded from the analysis. Using Rv.3.3.3., the frequencies of PVs by sex, number of cancers and age at diagnosis were compared using two-sided χ2 tests or Fisher’s exact test when the number was < 10. Results: Of the 9820 patients with MPCs tested for the 21 genes above, 104 (1.1%) had multiple PVs and were excluded. Among the remaining 9716 patients in the analytic cohort, most were female (91.1%) and white (71.0%). The median age at testing was 63 years (IQR: 16) and the median ages of first and second cancer diagnosis were 49 (IQR: 18) and 58 (IQR: 17) years, respectively. Overall, 1406 (14.5%) were found to have PVs: 14.3% of females and 16.2% of males. The prevalence of PVs increased with the number of primary cancers (PCs) as follows, 2 PCs: 13.1% (95% CI:12.4-13.8%), 3 PCs: 15.9% (95% CI:14.0-18.0%), >4 PCs: 18.0% (95% CI:13.7-23.3%), (p < 0.01). Among patients with 2 PCs (n = 8145), differences in the prevalence of PVs by age at diagnosis were significant: 2 PCs diagnosed at an age < 50 (13.5%, 95% CI:12.0-15.1%), 1 PC diagnosed at an age < 50 (14.8%, 95% CI:13.4-16.5%), 2 PCs diagnosed at age >50 years (12.1%, 95% CI: 11.1-13.2%), (p = 0.01). PVs were most frequently identified in: BRCA2 (2.2%) BRCA1 (2.0%), CHEK2 (1.9%) and ATM (1.5%). There were also significant differences in the frequencies of PVs in BRCA1, BRCA2 and MLH1 by sex (p < 0.05). Conclusions: These data demonstrate a high frequency of germline PVs among both males and females with MPC. The frequency of PVs was higher among patients with a higher number of PCs. Differences in the prevalence of PVs by age at cancer diagnosis while significant, were not meaningful as 12.1% of individuals with 2 PCs diagnosed at age >50 years had germline PVs. Limitations include the homogenous testing population (predominately female and white) and small numbers in some patient categories. These data may aid in counseling patients with MPCs and their families as well as encourage less restrictive genetic testing of this population. Further analysis of PV frequencies by specific cancer combinations was conducted and will follow.

10501 Background: Multigene panel testing (MGPT) has identified TP53 pathogenic or likely pathogenic (P/LP) variants in patients with diverse phenotypes from no cancer to classic Li-Fraumeni syndrome (LFS). There is increasing recognition of variants at low allelic fraction (VAF) for TP53 in particular, which can be suggestive of post-zygotic mosaicism or aberrant clonal expansion (ACE), comprising clonal hematopoiesis of indeterminate potential (CHIP) or occult hematologic neoplasia. Distinguishing among these categories is essential because of widely different cancer risk and management implications for patients and their relatives. We report an evaluation of TP53 positive probands to determine germline versus somatic status from a cancer genetics clinic. Methods: We reviewed probands with TP53 P/LP variants by MGPT on blood (N = 83) or saliva (N = 1) samples from 2012-2019. Available VAFs were collected from commercial testing laboratories. Probands positive for a known familial variant, who met LFS testing criteria without indication of low VAF, or who carried the Brazil founder p.R337H variant were considered germline. For those with uncertain germline status, data was obtained from ancillary testing of family members, cultured skin fibroblasts, and other somatic benign or tumor tissues. TP53 variants were further categorized based on all available data. Results: Of the 84 probands, 28 (33%) had germline TP53 P/LP variants determined by above initial criteria; 18 (21%) were confirmed germline through ancillary testing. Seven (8%) individuals were classified as having constitutional mosaicism. In eleven (13%) individuals, the TP53 variants were consistent with ACE, in 9 (11%) with CHIP and in 2 (2%) with a hematologic malignancy (1 CLL, 1 NHL). Five (6%) cases could not be categorized despite ancillary testing. Fifteen (18%) probands declined any further workup. Conclusions: A TP53 P/LP variant found on peripheral blood or saliva MGPT does not always originate in the germline. In a clinical cancer genetics cohort, only 54% of patients had TP53 P/LP germline variants; these patients plus those with constitutional mosaicism (8%) require intensified surveillance. Assessment of VAF, family member testing, and analysis of TP53 in cultured fibroblasts or other tissue samples may distinguish germline and constitutional mosaic variants from the ACE spectrum. Expanding use of MGPT will increase this clinical challenge, which may motivate the modification of lab reports to include VAF and possible non-germline explanations. The findings of this study support a framework of multiple strategies to discern true constitutional status of a TP53 P/LP variant.

Background: There is evidence that increases in germline cancer genetic testing result in higher rates of contralateral prophylactic mastectomy (CPM) in newly diagnosed breast cancer (BC) patients, even among those with negative results. Unlike carriers of BRCA pathogenic variants (PV), the risks of contralateral breast cancer (CBC) and benefits of CPM for women with PV in moderate penetrance genes are not well studied. There is a critical need to determine how to best counsel BC patients about their personal CBC risk and surgical decisions. Trial design: Newly diagnosed BC patients are randomized 1:1 to quantitative or standard post-genetic test cancer risk counseling methods by genetic counselors. Quantitative counseling includes personalized CBC risk estimates. For patients with a PV in a BC risk gene, CBC risk estimates are calculated via the “ASK2ME” decision tool (https://ask2me.org/). For those without a BC-associated PV, CBC risk estimates are calculated via a validated model “CBCRisk” (https://cbc-predictor-utd.shinyapps.io/CBCRisk/).Standard counseling does not typically include specific CBC risk estimates.Eligibility criteria: All patients over 18 with newly diagnosed invasive or in situ unilateral BC considering genetic testing at Dana-Farber/Brigham and Women’s Cancer Center are eligible. Exclusion criteria include a diagnosis of previous BC, metastatic or bilateral BC, hematologic malignancy, prior or active other malignancy, prior multi-gene panel testing, known medical or surgical contraindication to surgery and/or CPM.Specific aims: The primary aims are to 1) compare changes in patients’ personal CBC risk assessment before/after quantitative versus standard counseling; 2) determine changes in patients’ propensity to choose CPM before/after quantitative versus standard counseling. The secondary aims are to: 1) compare CPM rates; 2) determine concordance between patient and surgeon assessment of CBC risk; 3) evaluate patient genetic testing satisfaction via the Genetic Testing Satisfaction Survey administered post-counseling; 4) measure patient anxiety via the PROMIS Anxiety Survey administered pre- and post-counseling, at 6 months and 2 years; and 5) measure patient decisional regret for both undergoing genetic testing and their surgery choices at 6 months and 2 years; all by quantitative versus standard counseling arms. Statistical methods: For aim 1, the difference between patients’ reported personal CBC risk and true risk before and after counseling will be determined. True risk will be based on the ASK2ME/CBCRisk estimates. We hypothesize that the difference between the true and estimated risk will be smaller post-counseling, and smaller in the quantitative counseling versus standard arm. Assuming an expected difference of 5% and expected standard deviation of 20%, 199 patients are needed for each arm to achieve 80% power and type I error of 5% (based on a two-sample t-test). For aim 2, to determine propensity to undergo CPM, patient responses will be assigned a numeric value: Very Unlikely (1), Somewhat unlikely (2), Unsure (3), Somewhat likely (4), Very likely (5). For each patient we will then calculate the difference in scores before/after counseling. Our hypothesis is that differences will be greater in the quantitative arm. Assuming an expected difference of 0.8 and expected standard deviation of 3, 175 patients are needed for each arm to achieve 80% power and type I error rate of 5% (based on a two-sample t-test). Accrual: Recruitment began on June 8, 2020; there are currently 9 of the target 450 patients enrolled. Funding Support: Sponsored Research Agreement with Myriad Laboratories, Inc. and a Brigham and Women’s Hospital Department of Surgery Robert T. Osteen Junior Fellowship Award. PI: Anna Weiss, aweiss5@bwh.harvard.edu, @DrAnnaWeiss Citation Format: Anna Weiss, Danielle Braun, Jill Stopfer, Daniel Desantis, Meaghan Dwan, Dillon Davis, Anjali Jha, Laura Dominici, Shoshana Rosenberg, Tari A. King, Elizabeth A Mittendorf, Mehra Golshan, Huma Q Rana, Judy E Garber. Genetic testing for all breast cancer patients (get facts) [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr OT-20-01.

1507 Background: Approximately 10% of men with advanced prostate cancer (PC) have pathogenic/likely pathogenic variants (PV) in cancer susceptibility genes and their identification may lead to targeted therapy. Genetic testing (GT) can also guide cancer surveillance and prevention for family members. While GT is recommended for men with potentially lethal PC, traditional testing models are strained, and access limited. The ProGen study examined a novel pretest model aimed at providing access to GT while promoting informed consent. Methods: Inclusion criteria were: potentially lethal PC (metastatic, localized with Gleason score ≥8, rising/persistent PSA after local therapy), diagnosis age ≤ 55 years, prior malignancy, family history suggestive of a PV and/or at oncologist’s discretion. Consented subjects from 3 sites were randomized 3:1 to video education (VE) or in-person genetic counseling (GC). Subjects who consented to GT had 67 genes analyzed (Ambry, USA) with results disclosed by telephone by a genetic counselor. Outcomes included GT uptake, PV prevalence, and survey measures of satisfaction, distress, genetics knowledge, family communication, and impact on cancer care (obtained at the time of intervention, and at 1, 4, and 12 months after result disclosure). Two-sided Fischer exact tests were used for between-arm comparisons. Results: Over a 2-year period: 662 subjects were randomized, VE or GC were completed by 604 subjects (VE: 93.1%, GC: 88.8%) of whom 596 subjects (VE:98.9%, GC:97.9%) consented to GT. To date, 591 subjects have completed GT (VE: 99.3%, GC: 98.6%). At the time of intervention, most subjects agreed or strongly agreed that their assigned arm was useful (VE: 95%, GC: 88%). Differences were not statistically significant. Notably, 84 PV were identified in 78 subjects (13.2%), with BRCA1/2 PV accounting for 32% of subjects with a positive result ( BRCA2:21, BRCA1:4). Conclusions: In this randomized trial, both novel VE and traditional GC yielded high GT uptake without significant differences in outcome measures of acceptability and satisfaction. VE enabled access to critical GT results while maintaining the core tenants of informed consent. PV were found in 13.2% of subjects, 32% of whom had BRCA1/2 PV. Analysis of collected survey data to inform strengths and limitations of VE as compared with pretest GC will be presented. Clinical trial information: NCT03328091.

659 Background: Hereditary RCCs account for 3-5% of all RCC cases. The prevalence and significance of germline PVs of RCC have not been fully characterized. Methods: We evaluated the frequency of pathogenic and likely pathogenic variants, referred to as PVs, in 1829 high-risk RCC pts who underwent targeted clinical germline testing (1-134 genes) at a commercial laboratory. PVs, including single nucleotide variants/indels/ copy number variants, were confirmed using orthogonal technology in accordance with Invitae’s standard operating practices. Actionable genes were defined as established cancer-predisposition genes that confer a higher risk for any cancer phenotype and for which enhanced screening and family genetic testing are recommended by the National Comprehensive Cancer Network. We focused our analysis on genes tested in more than 100 pts (n=93). Results: Among 1892 pts, 54.9% were male, and 68.9% were Caucasians, with median age 50 (range:1-87) years at RCC diagnosis. 11.8% (n=215) of pts had at least 2 primary RCCs, and 30.7% (n= 561) had a personal history of another cancer. The cumulative frequency of pts with PVs was 17.7%. PVs in known RCC susceptibility genes such as FH, FLCN, and SDHB were detected in 1.8% (29/1622), 1.22% (120/1634) and 0.64% (11/1727) of pts respectively. PVs in other cancer-associated genes were most frequently reported in CHEK2 (loss-of-function variants, 30/1276, 2.4%), MUTYH (19/1124, 1.7%), and BRCA2 (17/1276, 1.33%). PVs in DNA-damage repair genes (DRG) accounted for 71.8% of PVs and, overall, were detected in 12.7% of pts. Among the DRG, PVs in the homologous recombination pathway (ATM, BARD1, BLM, BRCA1, BRCA2, BRIP1, CHEK2, NBN, PALB2, RECQL4, WRN) were the most prevalent (7.8%) whereas the mismatch repair pathway (MLH1, MSH2, MSH6, PMS2) was altered in only 0.7% of pts. Of the examined cohort, 9.7% of pts had ≥1 actionable PV. In non-Caucasians, BRCA2 PVs were the most common (6/273, 2.20%). Conclusions: PVs were identified in 17.7% of RCC subjects, most of which (71.8%) were in DRG, with »10% of pts having actionable variants. Our work is concordant with known RCC susceptibility genes and potentially highlights novel risk genes that should be validated in future studies.

Transgender individuals comprise a growing patient population in genetic counseling practice. The identification of a pathogenic variant in a cancer susceptibility gene may impact a transgender person's decisions regarding hormonal and/or surgical transition. Limited scientific literature exists on specific genetic counseling needs and medical management strategies for transgender individuals. In addition, most genetic counselors have had limited experience and training in conducting genetic counseling sessions with transgender patients. In this report, we describe three cases of transgender individuals who underwent genetic counseling and testing in our clinic. All were at ≥50% risk to carry a familial BRCA1 pathogenic variant. Case 1 is a 20-year-old transgender female initiating hormonal agents. Case 2 is a 19-year-old transgender male considering surgical decisions who has a BRCA1 pathogenic variant on both sides of the family. Case 3 is a 24-year-old transgender male who had previously undergone gender-affirming mastectomy (top surgery) and is taking androgen therapy. Unique aspects of genetic testing, psychosocial counseling, and medical management of transgender individuals have arisen in the course of their care. In this report, we discuss our experiences and practices of case preparation, case management, appropriate genetic testing, and medical management such as screening, surgical decisions, and coordination of care. There is a need for more research in this area and more transgender-specific training for genetic counselors.

The current algorithm for Lynch syndrome diagnosis is highly complex with multiple steps which can result in an extended time to diagnosis while depleting precious tumor specimens. Here we describe the analytical validation of a custom probe-based NGS tumor panel, TumorNext-Lynch-MMR, which generates a comprehensive genetic profile of both germline and somatic mutations that can accelerate and streamline the time to diagnosis and preserve specimen. TumorNext-Lynch-MMR can detect single nucleotide variants, small insertions and deletions in 39 genes that are frequently mutated in Lynch syndrome and colorectal cancer. Moreover, the panel provides microsatellite instability status and detects loss of heterozygosity in the five Lynch genes; MSH2, MSH6, MLH1, PMS2 and EPCAM. Clinical cases are described that highlight the assays ability to differentiate between somatic and germline mutations, precisely classify variants and resolve discordant cases.