Diagnostic yield of multigene panel testing in an Israeli cohort: enrichment of low-penetrance variants.

BACKGROUND: Carriers of pathogenic variants (PVs) in moderate-high-penetrance cancer susceptibility genes are offered tailored surveillance schemes for early cancer diagnosis. The clinical implications of low-penetrance variant carriers are less clear. METHODS: Clinical and demographic data were retrieved for a cohort of Israeli individuals who underwent oncogenetic testing by the 30-gene cancer panel at Color Genomics laboratory, between 04/2013 and 12/2018. RESULTS: Of 758 genotyped individuals, 504 had been diagnosed with cancer prior to testing: 283 (56%) had breast cancer and 106 (21%) colorectal cancer. Pathogenic or likely pathogenic (P/LP) variants were detected in 123 (16%) individuals. Overall, 44 different P/LP variants were detected in 18/30 cancer susceptibility genes; 20 of them were founder/recurrent mutations. Of the carriers, 39 (32%), 10 (8%), and 74 (60%) carried high-, moderate-, or low-penetrance variants, respectively. After excluding low-penetrance variants, 7% (33/504) of all cancer patients, 6% of breast or ovarian cancer patients were found to be carriers, as well as 7% (14/203) of individuals with colonic polyps, and 4% (11/254) of cancer-free individuals. CONCLUSIONS: The diagnostic yield of moderate- and high-penetrance PVs using multigene panel testing was 6%, with 3.7% carriers of non-recurrent PVs. This yield should be discussed during pre-test counseling, and emphasizes the need for harmonized recommendations regarding clinical implications of low-penetrance variants.

Variable Features of Juvenile Polyposis Syndrome With Gastric Involvement Among Patients With a Large Genomic Deletion of BMPR1A.

OBJECTIVES: Loss-of-function mutations of BMPR1A cause juvenile polyposis syndrome (JPS), but large genomic deletions in BMPR1A are rare, reported in few families only, and data regarding the associated phenotype are limited. METHODS: We investigated clinical features and genomic data of 7 extended seemingly unrelated families with a genomic deletion of the entire coding region of BMPR1A. We defined mutation size, mutation prevalence, and tumor pathogenesis using whole-genome sequencing, targeted genotyping, and haplotype analysis. RESULTS: Patients with JPS from 7 families of Bukharin Jewish ancestry carried a deletion of 429 kb, encompassing the BMPR1A coding sequence and 8 downstream genes. Haplotype analysis and testing controls identified this as a common founder mutation occurring in 1/124 individuals of Bukharin origin. Tumor testing did not demonstrate loss of heterozygosity. Among carriers, JPS was almost fully penetrant, but clinical features varied widely, ranging from mild to very severe, including pan-enteric polyps, gastritis, and colorectal, esophageal, and testicular cancer, and carriers with phenotypes, which would not have raised suspicion of JPS. DISCUSSION: The phenotype in this large cohort was extremely variable, although all carriers shared the same variant and the same genetic background. New observations include a preponderance of adenomatous rather than juvenile polyps, possible association with testicular cancer, and unexpected upper gastrointestinal involvement.

Personalized prostate cancer screening among men with high risk genetic predisposition- study protocol for a prospective cohort study.

BACKGROUND: Prostate cancer screening among the general population is highly debatable. Nevertheless, screening among high-risk groups is appealing. Prior data suggests that men carrying mutations in the BRCA1& 2 genes may be at increased risk of developing prostate cancer. Additionally, they appear to develop prostate cancer at a younger age and with a more aggressive course. However, prior studies did not systematically perform prostate biopsies and thus cannot determine the true prevalence of prostate cancer in this population. METHODS: This will be a prospective diagnostic trial of screening for prostate cancer among men with genetic predisposition. The target population is males (40-70 year old) carrying a BRCA1 and/or BRCA2 germ line mutation. They will be identified via our Genetic counseling unit. All men after signing an informed consent will undergo the following tests: PSA, free to total PSA, MRI of prostate and prostate biopsy. The primary endpoint will be to estimate the prevalence, stage and grade of prostate cancer in this population. Additionally, the study aims to estimate the impact of these germ line mutations on benign prostatic hyperplasia. Furthermore, this study aims to create a bio-bank of tissue, urine and serum of this unique cohort for future investigations. Finally, this study will identify an inception cohort for future interventional studies of primary and secondary prevention. DISCUSSION: The proposed research is highly translational and focuses not only on the clinical results, but on the future specimens that will be used to advance our understanding of prostate cancer patho-physiology. Most importantly, these high-risk germ-line mutation carriers are ideal candidates for primary and secondary prevention initiatives. TRIAL REGISTRATION: ClinicalTrials.gov: NCT02053805.