Simple Summary Genetic variants explaining approximately 40% of familial breast cancer risk have been identified, thus leaving a significant fraction of the heritability of this disease still... Show moreSimple Summary Genetic variants explaining approximately 40% of familial breast cancer risk have been identified, thus leaving a significant fraction of the heritability of this disease still unexplained. The exact nature of this missing fraction is unknown; more extensive sequencing efforts could potentially identify new moderate-penetrance breast cancer risk alleles. The aim of this study was to perform a large-scale whole-exome sequencing study, followed by a targeted validation, in breast cancer patients and healthy women of European descent. We identified 20 novel genes with modest evidence of association (p-value < 0.05) for either overall or subtype-specific breast cancer; however, much larger studies are needed to confirm the exact role of these genes in susceptibility to breast cancer. Rare variants in at least 10 genes, including BRCA1, BRCA2, PALB2, ATM, and CHEK2, are associated with increased risk of breast cancer; however, these variants, in combination with common variants identified through genome-wide association studies, explain only a fraction of the familial aggregation of the disease. To identify further susceptibility genes, we performed a two-stage whole-exome sequencing study. In the discovery stage, samples from 1528 breast cancer cases enriched for breast cancer susceptibility and 3733 geographically matched unaffected controls were sequenced. Using five different filtering and gene prioritization strategies, 198 genes were selected for further validation. These genes, and a panel of 32 known or suspected breast cancer susceptibility genes, were assessed in a validation set of 6211 cases and 6019 controls for their association with risk of breast cancer overall, and by estrogen receptor (ER) disease subtypes, using gene burden tests applied to loss-of-function and rare missense variants. Twenty genes showed nominal evidence of association (p-value < 0.05) with either overall or subtype-specific breast cancer. Our study had the statistical power to detect susceptibility genes with effect sizes similar to ATM, CHEK2, and PALB2, however, it was underpowered to identify genes in which susceptibility variants are rarer or confer smaller effect sizes. Larger sample sizes would be required in order to identify such genes. Show less
BackgroundCHEK2 has been recognized as a breast cancer risk gene with moderate effect. Women who have previously tested negative for a BRCA1/2 gene germline pathogenic variant may benefit from... Show moreBackgroundCHEK2 has been recognized as a breast cancer risk gene with moderate effect. Women who have previously tested negative for a BRCA1/2 gene germline pathogenic variant may benefit from additional genetic testing for the CHEK2 c.1100del pathogenic variant. The aims of this study were: 1) to assess the uptake of an active approach by recontacting BRCA1/2-negative women for additional CHEK2 c.1100del testing on stored DNA-samples and 2) to explore patients' experiences with this approach.MethodsBetween 2015 and 2017, women who had been tested earlier negative for BRCA1/2 germline pathogenic variants, were recontacted for additional CHEK2 c.1100del testing on stored DNA-samples, free-of-charge. They received an information letter about the CHEK2 pathogenic variant and could return an informed consent form when they opted for additional genetic testing. Those in whom the CHEK2 pathogenic variant was absent, received a letter describing this result. Those who tested positive, were invited for a personal counseling at the department of genetics. On average 21months (range 4-27) after the genetic test result, a questionnaire was sent to all identified carriers and a control group of women who tested negative for the pathogenic variant to explore patients' experiences with our approach.ResultsIn total, 70% (N=1666) of the N=2377 women contacted opted for additional testing, and 66 (4%) of them proved to be carriers of the CHEK2 c.1100del pathogenic variant. Regardless of the outcome of the genetic test, women were generally satisfied with our approach and reported that the written information was sufficient to make an informed decision about the additional CHEK2 testing.ConclusionsThe uptake (70%) of our approach was considered satisfactory. Patients considered the benefits more important than the psychosocial burden. Given the rapid developments in DNA-diagnostics, our findings may support future initiatives to recontact patients about additional genetic testing when they previously tested negative for a pathogenic variant in a breast cancer gene. Show less
Pathogenic sequence variants (PSV) in BRCA1 or BRCA2 (BRCA1/2) are associated with increased risk and severity of prostate cancer. Weevaluated whether PSVs inBRCA1/2 were associated with risk of... Show morePathogenic sequence variants (PSV) in BRCA1 or BRCA2 (BRCA1/2) are associated with increased risk and severity of prostate cancer. Weevaluated whether PSVs inBRCA1/2 were associated with risk of overall prostate cancer or high grade (Gleason 8+) prostate cancer using an international sample of 65 BRCA1 and 171 BRCA2 male PSV carriers with prostate cancer, and 3,388 BRCA1 and 2,880 BRCA2 male PSV carriers without prostate cancer. PSVs in the 30 region of BRCA2 (c.7914+) were significantly associated with elevated risk of prostate cancer compared with reference bin c.1001c.7913 [HR = 1.78; 95% confidence interval (CI), 1.25-2.52; P = 0.001], as well as elevated risk of Gleason 8+ prostate cancer (HR = 3.11; 95% CI, 1.63-5.95; P = 0.001). c.756-c.1000 was also associated with elevated prostate cancer risk (HR = 2.83; 95% CI, 1.71-4.68; P = 0.00004) and elevated risk of Gleason 8+prostate cancer (HR = 4.95; 95% CI, 2.12-11.54; P = 0.0002). No genotype-phenotype associations were detected for PSVs in BRCA1. These results demonstrate that specific BRCA2 PSVs may be associated with elevated risk of developing aggressive prostate cancer.Significance: Aggressive prostate cancer risk in BRCA2 mutation carriers may vary according to the specific BRCA2 mutation inherited by the at-risk individual. Show less
Purpose: Whether endometrial carcinoma (EC) should be considered part of the gBRCA1/2-associated hereditary breast and ovarian cancer (HBOC) syndrome is topic of debate. We sought to assess whether... Show morePurpose: Whether endometrial carcinoma (EC) should be considered part of the gBRCA1/2-associated hereditary breast and ovarian cancer (HBOC) syndrome is topic of debate. We sought to assess whether ECs occurring in gBRCA carriers are enriched for clinicopathologic and molecular characteristics, thereby supporting a causal relationship.Experimental Design: Thirty-eight gBRCA carriers that developed EC were selected from the nationwide cohort study on hereditary breast and ovarian cancer in the Netherlands (HEBON), and these were supplemented with four institutional cases. Tumor tissue was retrieved via PALGA (Dutch Pathology Registry). Nineteen morphologic features were scored and histotype was determined by three expert gyneco-logic pathologists, blinded for molecular analyses (UCM-OncoPlus Assay including 1213 genes). ECs with LOH of the gBRCA-wild-type allele (gBRCA/LOHpos) were defined "gBRCA-associated," those without LOH (gBRCA/LOHneg) were defined "sporadic."Results: LOH could be assessed for 40 ECs (30 gBRCA1, 10 gBRCA2), of which 60% were gBRCA/LOHpos. gBRCA/LOHpos ECs were more frequently of nonendometrioid (58%, P = 0.001) and grade 3 histology (79%, P < 0.001). All but two were in the TP53-mutated TCGA-subgroup (91.7%, P < 0.001). In contrast, gBRCA/LOHneg ECs were mainly grade 1 endometrioid EC (94%) and showed a more heterogeneous distribution of TCGA-molecular subgroups: POLE-mutated (6.3%), MSI-high (25%), NSMP (62.5%), and TP53-mutated (6.3%).Conclusions: We provide novel evidence in favor of EC being part of the gBRCA-associated HBOC-syndrome. gBRCA-associated ECs are enriched for EC subtypes associated with unfavorable clinical outcome. These findings have profound therapeutic consequences as these patients may benefit from treatment strategies such as PARP inhibitors. In addition, it should influence counseling and surveillance of gBRCA carriers. Show less
Teixeira, N.; Hout, A. van der; Oosterwijk, J.C.; Vos, J.R.; Devilee, P.; Engelen, K. van; ... ; HEBON 2018
Eijkelenkamp, K.; Olderode-Berends, M.J.W.; Luijt, R.B. van der; Robledo, M.; Dooren, M. van; Feelders, R.A.; ... ; Horst-Schrivers, A.N.A. van der 2018
AbstractBACKGROUND: We previously showed that the BRCA1 variant c.5096G>A p.Arg1699Gln (R1699Q) was associated with an intermediate risk of breast cancer (BC) and ovarian cancer (OC). This study... Show moreAbstractBACKGROUND: We previously showed that the BRCA1 variant c.5096G>A p.Arg1699Gln (R1699Q) was associated with an intermediate risk of breast cancer (BC) and ovarian cancer (OC). This study aimed to assess these cancer risks for R1699Q carriers in a larger cohort, including follow-up of previously studied families, to further define cancer risks and to propose adjusted clinical management of female BRCA1*R1699Q carriers.METHODS: Data were collected from 129 BRCA1*R1699Q families ascertained internationally by ENIGMA (Evidence-based Network for the Interpretation of Germline Mutant Alleles) consortium members. A modified segregation analysis was used to calculate BC and OC risks. Relative risks were calculated under both monogenic model and major gene plus polygenic model assumptions.RESULTS: In this cohort the cumulative risk of BC and OC by age 70 years was 20% and 6%, respectively. The relative risk for developing cancer was higher when using a model that included the effects of both the R1699Q variant and a residual polygenic component compared with monogenic model (for BC 3.67 vs 2.83, and for OC 6.41 vs 5.83).CONCLUSION: Our results confirm that BRCA1*R1699Q confers an intermediate risk for BC and OC. Breast surveillance for female carriers based on mammogram annually from age 40 is advised. Bilateral salpingo-oophorectomy should be considered based on family history. Show less
Dommering, C.J.; Henneman, L.; Hout, A.H. van der; Jonker, M.A.; Tops, C.M.J.; Ouweland, A.M.W. van den; ... ; Meijers-Heijboer, H. 2017
