A clinical guide to hereditary cancer panel testing: evaluation of gene-specific cancer associations and sensitivity of genetic testing criteria in a cohort of 165,000 high-risk patients.

PURPOSE: Despite the rapid uptake of multigene panel testing (MGPT) for hereditary cancer predisposition, there is limited guidance surrounding indications for testing and genes to include. METHODS: To inform the clinical approach to hereditary cancer MGPT, we comprehensively evaluated 32 cancer predisposition genes by assessing phenotype-specific pathogenic variant (PV) frequencies, cancer risk associations, and performance of genetic testing criteria in a cohort of 165,000 patients referred for MGPT. RESULTS: We identified extensive genetic heterogeneity surrounding predisposition to cancer types commonly referred for germline testing (breast, ovarian, colorectal, uterine/endometrial, pancreatic, and melanoma). PV frequencies were highest among patients with ovarian cancer (13.8%) and lowest among patients with melanoma (8.1%). Fewer than half of PVs identified in patients meeting testing criteria for only BRCA1/2 or only Lynch syndrome occurred in the respective genes (33.1% and 46.2%). In addition, 5.8% of patients with PVs in BRCA1/2 and 26.9% of patients with PVs in Lynch syndrome genes did not meet respective testing criteria. CONCLUSION: Opportunities to improve upon identification of patients at risk for hereditary cancer predisposition include revising BRCA1/2 and Lynch syndrome testing criteria to include additional clinically actionable genes with overlapping phenotypes and relaxing testing criteria for associated cancers.

Cancer Incidence in First- and Second-Degree Relatives of BRCA1 and BRCA2 Mutation Carriers.

BACKGROUND: Mutations in the BRCA1 and BRCA2 genes are associated with increased risk of breast, ovarian, and several other cancers. The purpose of the present study was to evaluate the incidence of cancer in first- and second-degree relatives of BRCA mutation carriers compared with the general population. MATERIALS AND METHODS: A total of 1,086 pedigrees of BRCA mutation carriers was obtained from a prospectively maintained, internal review board-approved study of persons referred for clinical genetic counseling at the University of Texas MD Anderson Cancer Center. We identified 9,032 first- and second-degree relatives from 784 pedigrees that had demonstrated a clear indication of parental origin of mutation. Standardized incidence ratios (SIRs) were used to compare the observed incidence of 20 primary cancer sites to the expected incidence of each cancer based on the calculated risk estimates according to each subject's age, sex, and ethnicity. RESULTS: BRCA1 families had increased SIRs for breast and ovarian cancer (p < .001) and decreased SIRs for kidney, lung, prostate, and thyroid cancer and non-Hodgkin's lymphoma (p < .001). BRCA2 families had increased SIRs for breast, ovarian, and pancreatic cancer (p < .001) and decreased SIRs for kidney, lung, thyroid, and uterine cancer and non-Hodgkin's lymphoma (p < .0025). Analysis of only first-degree relatives (n = 4,099) identified no decreased SIRs and agreed with the increased SIRs observed in the overall study population. CONCLUSION: We have confirmed previous reports of an association between breast, ovarian, and pancreatic cancers with BRCA mutations. Additional research to quantify the relative risks of these cancers for BRCA mutation carriers can help tailor recommendations for risk reduction and enhance genetic counseling. IMPLICATIONS FOR PRACTICE: BRCA gene mutations have been well described to carry an increased risk of both breast and ovarian cancer. However, the implications and risks of other cancers continues to be investigated. Evaluating the risks for other cancers further is key in identifying and managing risk reduction strategies.

High incidence of germline BRCA mutation in patients with ER low-positive/PR low-positive/HER-2 neu negative tumors.

BACKGROUND: The 2015 National Comprehensive Cancer Network guidelines recommend that genetic counseling and germline BRCA mutation testing be offered to women under age 60 with triple-negative breast cancer (TNBC). As a result of the 2010 American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP) guidelines for breast cancer, patients with breast cancers that are estrogen receptor (ER) or progesterone receptor (PR) low-positive (1%-9% on immunohistochemistry) are no longer strictly considered to have TNBC and may not be referred for genetic counseling. However, the incidence of BRCA mutation in patients with hormone receptor (HR) low-positive breast cancers remains unknown, and current ASCO/CAP guidelines may result in undertesting for BRCA mutations. METHODS: A prospectively maintained research database of breast cancer patients evaluated at The University of Texas MD Anderson Cancer Center between 2004 and 2014 was reviewed; 314 patients were identified with HER2/neu-negative breast cancers expressing ER and PR <10% with known BRCA mutation status. RESULTS: Three hundred fourteen patients had breast cancers expressing ER and PR <10%; 238 (75.8%) had HR-negative cancers (<1% ER and PR), and 76 (24.2%) had HR-low-positive cancers (1%-9% ER and/or PR). Among patients with HR-negative tumors, 86 of 238 (36.1%) had a BRCA1/2 mutation, whereas in the HR-low-positive group, 30 of 76 (39.5%) had a BRCA1/2 mutation. In multivariate analysis, HR status (<1% vs 1%-9%) was not significantly associated with BRCA1/2 mutations. CONCLUSIONS: The incidence of BRCA1/2 mutations is similar in patients with HR-low-positive breast cancer and patients with HR-negative breast cancer. Genetic counseling and BRCA testing should be offered to patients under age 60 who have HR-low-positive breast cancers. Cancer 2015;121:3435-43. © 2015 American Cancer Society.

Genetic risk assessment for breast and gynecological malignancies.

PURPOSE OF REVIEW: Breast cancer and gynecological cancers impact a significant portion of women each year. Identifying women at high risk is essential for implementation of screening and risk reduction recommendations. Risk assessment for these cancers involves an evaluation of many factors. This review discusses an overview of hereditary breast and gynecological cancers and the process of a cancer genetic risk assessment. RECENT FINDINGS: Risk assessment models for breast cancer should be used with caution, especially in populations in which they are not validated. Additionally, the BRCAPRO model may underestimate the likelihood of BRCA mutations in certain populations.The utilization of next-generation sequencing panels is increasing. Benefits and limitations of panel testing are described in the literature. There are currently no guidelines for the use of panel testing; however, some reports of institutional experiences and recommendations are available. SUMMARY: Cancer genetic risk assessment is complex, and models developed to estimate risk may not apply to all populations. Identifying genetic factors related to cancer risk is also becoming increasingly complex with the clinical implementation of panel testing. This testing approach should be critically evaluated by healthcare providers. Further research is needed to create evidence-based guidelines for panel testing and management recommendations for moderately penetrant genes.

Breast cancer, BRCA mutations, and attitudes regarding pregnancy and preimplantation genetic diagnosis.

BACKGROUND: Women with premenopausal breast cancer may face treatment-related infertility and have a higher likelihood of a BRCA mutation, which may affect their attitudes toward future childbearing. METHODS: Premenopausal women were invited to participate in a questionnaire study administered before and after BRCA genetic testing. We used the Impact of Event Scale (IES) to evaluate the pre- and post-testing impact of cancer or carrying a BRCA mutation on attitudes toward future childbearing. The likelihood of pursuing prenatal diagnosis (PND) or preimplantation genetic diagnosis (PGD) was also assessed in this setting. Univariate analyses determined factors contributing to attitudes toward future childbearing and likelihood of PND or PGD. RESULTS: One hundred forty-eight pretesting and 114 post-testing questionnaires were completed. Women with a personal history of breast cancer had less change in IES than those with no history of breast cancer (p = .003). The 18 BRCA-positive women had a greater change in IES than the BRCA-negative women (p = .005). After testing, 31% and 24% of women would use PND and PGD, respectively. BRCA results did not significantly affect attitudes toward PND/PGD. CONCLUSION: BRCA results and history of breast cancer affect the psychological impact on future childbearing. Intentions to undergo PND or PGD do not appear to change after disclosure of BRCA results. Additional counseling for patients who have undergone BRCA testing may be warranted to educate patients about available fertility preservation options.

Assessing the integration of genomic medicine in genetic counseling training programs.

Medical genetics has entered a period of transition from genetics to genomics. Genetic counselors (GCs) may take on roles in the clinical implementation of genomics. This study explores the perspectives of program directors (PDs) on including genomic medicine in GC training programs, as well as the status of this integration. Study methods included an online survey, an optional one-on-one telephone interview, and an optional curricula content analysis. The majority of respondents (15/16) reported that it is important to include genomic medicine in program curricula. Most topics of genomic medicine are either "currently taught" or "under development" in all participating programs. Interview data from five PDs and one faculty member supported the survey data. Integrating genomics in training programs is challenging, and it is essential to develop genomics resources for curricula.

Mutational and splicing landscape in a cohort of 43,000 patients tested for hereditary cancer.

DNA germline genetic testing can identify individuals with cancer susceptibility. However, DNA sequencing alone is limited in its detection and classification of mRNA splicing variants, particularly those located far from coding sequences. Here we address the limitations of splicing variant identification and interpretation by pairing DNA and RNA sequencing and describe the mutational and splicing landscape in a clinical cohort of 43,524 individuals undergoing genetic testing for hereditary cancer predisposition.

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.

Comprehensive Paired Tumor/Germline Testing for Lynch Syndrome: Bringing Resolution to the Diagnostic Process.

PURPOSE: The current diagnostic testing algorithm for Lynch syndrome (LS) is complex and often involves multiple follow-up germline and somatic tests. We aimed to describe the results of paired tumor/germline testing performed on a large cohort of patients with colorectal cancer (CRC) and endometrial cancer (EC) to better determine the utility of this novel testing methodology. MATERIALS AND METHODS: We retrospectively reviewed a consecutive series of patients with CRC and EC undergoing paired tumor/germline analysis of the LS genes at a clinical diagnostic laboratory (N = 702). Microsatellite instability, MLH1 promoter hypermethylation, and germline testing of additional genes were performed if ordered. Patients were assigned to one of five groups on the basis of prior tumor screening and germline testing outcomes. Results for each group are described. RESULTS: Overall results were informative regarding an LS diagnosis for 76.1% and 60.8% of patients with mismatch-repair-deficient (MMRd) CRC and EC without and with prior germline testing, respectively. LS germline mutations were identified in 24.8% of patients in the group without prior germline testing, and interestingly, in 9.5% of patients with previous germline testing; four of these were discordant with prior tumor screening. Upon excluding patients with MLH1 promoter hypermethylation and germline mutations, biallelic somatic inactivation was seen in approximately 50% of patients with MMRd tumors across groups. CONCLUSION: Paired testing identified a cause for MMRd tumors in 76% and 61% of patients without and with prior LS germline testing, respectively. Findings support inclusion of tumor sequencing as well as comprehensive LS germline testing in the LS testing algorithm. Paired testing offers a complete, convenient evaluation for LS with high diagnostic resolution.

Service Delivery Model and Experiences in a Cancer Genetics Clinic for an Underserved Population.

This report describes a genetics clinic for hereditary breast and ovarian cancer (HBOC) in an underserved population. Genetic counseling was provided to 151 patients, and 131 underwent BRCA genetic testing. This was a unique, group-based establishment of an HBOC genetics clinic, which to our knowledge had not previously been reported.

Predictors that Influence Election of Contralateral Prophylactic Mastectomy among Women with Ductal Carcinoma in Situ who are BRCA-Negative.

The authors retrospectively examined the contralateral prophylactic mastectomy (CPM) rate among 100 women with ductal carcinoma in situ who are BRCA negative. Of 100 women with ductal carcinoma in situ, 31 elected contralateral prophylactic mastectomy (CPM). Factors associated with increased likelihood of undergoing contralateral prophylactic mastectomy (CPM) among this cohort were: family history of ovarian cancer, marital status, reconstruction, mastectomy of the affected breast, and tamoxifen use.

Breast cancer in the young: role of the geneticist.

The genetics professional plays an important role in the care of young women with breast cancer by providing counseling on issues specific to these young women. The issues addressed in counseling include hereditary predisposition to cancer, fertility and reproductive options in the context of hereditary cancer, and the impact and implications of their history of early breast cancer on close family members. A thorough risk assessment and counseling session address the patient's personal and family history, with particular attention paid to benign and malignant findings that suggest the need for genetic testing. Genetics professionals, especially genetic counselors, also address the physical and emotional implications of an increased risk of cancer with patients and family members. This review highlights the unique aspects of care provided by these specialized healthcare providers.