Evaluation of the needs of spouses of female carriers of mutations in BRCA1 and BRCA2

The process of genetic testing involves the entire family, including spouses. The objective of this study was to measure the specific needs and to describe the experiences of spouses of women who received genetic counseling for a positive BRCA1/2 result. We surveyed 59 spouses of female mutation carriers. The mean length of relationships was 26 years (range: 2.5-50 years). All were supportive of their spouses' decision to undergo genetic testing and counselling. Four respondents stated that they wished that they had received additional support at the time of test disclosure and 20% felt that their wives had received inadequate support. One-quarter of the spouses believed that their relationship had changed because of genetic testing; most felt that they had become closer to their wives. Husbands were most concerned about the risk of their wife dying of cancer (43%), followed by the risk of their spouse developing cancer (19%) and the risk that their children would test positive for the BRCA mutation (14%). Distress levels, measured by the Impact of Event scale, suggest that few spouses were experiencing clinical levels of distress.     

Cascade screening in BRCA1/2 mutation carriers

Genetic counselling for families with BRCA1 & 2 has been available in Ireland since 1998. We describe the follow-on cascade from the initial 29 index cases that tested positive for either gene. 28 of the index cases were female and 1 was male. Their combined sibship and offspring totalled 125 and 129 respectively. Of the 125 siblings, 21/72 (29%) females and 10/53 (19%) males came forward for counselling and all were tested. Of the 129 at risk offspring, 56 (43%) [25 females and 31 males] were over 18 years and therefore were eligible for testing. 20/25 (80%) females and 6/31 (19%) males came for counselling and all bar one female was tested. In summary, 31/125 (25%) at risk siblings were tested and 25/56 (45%) offspring were tested. Only one person, a daughter of an affected individual who attended clinic, declined testing. The remaining 197 (77%) individuals have not come forward for counselling. Our results suggest that a) there is a low-moderate testing rate in Ireland when compared to other European centres; and that b) daughters of BRCA1/2 carriers are more likely to come forward for testing than female siblings. Specific factors which appeared to influence attendance included poor dissemination of information among families about the test; and lower levels of communication among siblings than within the nuclear family.     

Uptake and timing of bilateral prophylactic salpingo-oophorectomy among BRCA1 and BRCA2 mutation carriers

PurposeTo evaluate prophylactic salpingo-oophorectomy uptake and timing among BRCA1/2 mutation carriers in a cancer risk assessment program.MethodsClinical records of female BRCA1/2 mutation carriers who received cancer genetic counseling between 1996 and 2003 were reviewed to determine the completion and the timing of prophylactic salpingo-oophorectomy. Logistic regression models evaluated associations between subject characteristics and surgery. Survival analysis methods were used to estimate the distribution of time to surgery.ResultsAmong 88 women, 70% underwent prophylactic salpingo-oophorectomy. Prophylactic salpingo-oophorectomy was associated with older age, white race, having children, and a family history of ovarian cancer. Many women waited more than 12 months to undergo surgery and some delayed by several years. Younger age and not having children were associated with delays to surgery.ConclusionProphylactic salpingo-ooporectomy is an acceptable risk reduction measure for many BRCA1/2 mutation carriers. Some women make this decision many years after genetic testing. Continued discussion of the risks and benefits of risk reduction options may facilitate the uptake of recommended risk reduction interventions among BRCA mutation carriers.     

Variant classification changes over time in BRCA1 and BRCA2

PurposeTo report BRCA1 and BRCA2 (BRCA1/2) variant reassessments and reclassifications between 2012 and 2017 at the Advanced Molecular Diagnostics Laboratory (AMDL) in Toronto, Canada, which provides BRCA1/2 testing for patients in Ontario, and to compare AMDL variant classifications with submissions in ClinVar.MethodsVariants were assessed using a standardized variant assessment tool based on the American College of Medical Genetics and Genomics/Association for Molecular Pathology’s guidelines and tracked in an in-house database. Variants were shared through the Canadian Open Genetics Repository and submitted to ClinVar for comparison against other laboratories.ResultsAMDL identified 1209 BRCA1/2 variants between 2012 and 2017. During this period, 32.9% (398/1209) of variants were reassessed and 12.4% (150/1209) were reclassified. The majority of reclassified variants were downgraded (112/150, 74.7%). Of the reclassified variants, 63.3% (95/150) were reclassified to benign, 20.7% (31/150) to likely benign, 10.0% (15/150) to variant of uncertain significance, 2.0% (3/150) to likely pathogenic, and 4.0% (6/150) to pathogenic. Discordant ClinVar submissions were found for 40.4% (488/1209) of variants.ConclusionBRCA1/2 variants may be reclassified over time. Reclassification presents ethical and practical challenges related to recontacting patients. Data sharing is essential to improve variant interpretation, to help patients receive appropriate care based on their genetic results.     

A survey of preventive measures among BRCA1 mutation carriers from Poland

Among women with a BRCA1 mutation, the lifetime risks of breast and ovarian cancer are elevated. Several measures for reducing cancer risk in carriers of BRCA1 mutations have been proposed, including prophylactic surgery and tamoxifen chemoprevention. It is not yet known to what extent women with mutations have adopted these various preventive measures. We surveyed 414 Polish women with a BRCA1 mutation who had received counseling about various preventive strategies. Each woman completed a survey for a minimum of 18 months after receiving her genetic result. A high proportion of women reported having had an oophorectomy to reduce breast and ovarian cancer risk (49.1%). In contrast, only 11% had taken tamoxifen and only 5% had undergone a preventive mastectomy. Most of the women (81%) had a screening mammogram during the follow-up period. Oral contraceptives and breastfeeding are believed to protect against ovarian cancer, but only 9% of women had taken the birth control pill for 3 years or more and 27% had breastfed for 1 year or more. In summary, approximately one-half of Polish women with a BRCA1 mutation had taken an active step to reduce their risk of breast cancer within 18 months of receiving a positive result. A greater effort should be made to promote breastfeeding and use of oral contraceptive as risk-reducing measures.     

Ovarian cancer susceptibility alleles and risk of ovarian cancer in BRCA1 and BRCA2 mutation carriers

Germline mutations in BRCA1 and BRCA2 are associated with increased risks of breast and ovarian cancer. A genome-wide association study (GWAS) identified six alleles associated with risk of ovarian cancer for women in the general population. We evaluated four of these loci as potential modifiers of ovarian cancer risk for BRCA1 and BRCA2 mutation carriers. Four single-nucleotide polymorphisms (SNPs), rs10088218 (at 8q24), rs2665390 (at 3q25), rs717852 (at 2q31), and rs9303542 (at 17q21), were genotyped in 12,599 BRCA1 and 7,132 BRCA2 carriers, including 2,678 ovarian cancer cases. Associations were evaluated within a retrospective cohort approach. All four loci were associated with ovarian cancer risk in BRCA2 carriers; rs10088218 per-allele hazard ratio (HR) = 0.81 (95% CI: 0.67-0.98) P-trend = 0.033, rs2665390 HR = 1.48 (95% CI: 1.21-1.83) P-trend = 1.8 × 10(-4), rs717852 HR = 1.25 (95% CI: 1.10-1.42) P-trend = 6.6 × 10(-4), rs9303542 HR = 1.16 (95% CI: 1.02-1.33) P-trend = 0.026. Two loci were associated with ovarian cancer risk in BRCA1 carriers; rs10088218 per-allele HR = 0.89 (95% CI: 0.81-0.99) P-trend = 0.029, rs2665390 HR = 1.25 (95% CI: 1.10-1.42) P-trend = 6.1 × 10(-4). The HR estimates for the remaining loci were consistent with odds ratio estimates for the general population. The identification of multiple loci modifying ovarian cancer risk may be useful for counseling women with BRCA1 and BRCA2 mutations regarding their risk of ovarian cancer.     

Multiple copies of mutant BRCA1 and BRCA2 alleles in breast tumors from germ-line mutation carriers

Inactivation of the BRCA1 and BRCA2 breast cancer susceptibility genes has been reported to occur via a germ-line mutation of one allele and a somatic loss of the remaining wild-type allele. We investigated the genetic mechanisms behind the second event in breast tumors from 17 BRCA1 and eight BRCA2 germ-line mutation carriers, as compared with 21 sporadic breast tumors. Microsatellite markers intragenic or in close proximity to both genes were used to analyze imbalances between the mutant and wild-type alleles. The actual and relative gene copy numbers were scored by fluorescence in situ hybridization (FISH) analysis of tumor cells using locus and centromere specific probes. All but one of the informative BRCA1 and BRCA2 tumors exhibited allelic imbalance and loss of the corresponding wild type allele. In contrast to sporadic tumors, however, where allelic imbalance at the BRCA1 and BRCA2 loci correlated well with relative copy number losses by FISH, a simple reduction to a single copy (average copy number ratio 2:1) was found in only two BRCA1 (12%) and four BRCA2 (50%) tumors. The majority of BRCA1 and BRCA2 tumors showed a copy number reduction (relative to reference probe with ratios 4:2, 3:2, 4:3) at corresponding loci, suggesting that a specific physical deletion of the wild-type BRCA gene allele has been followed by a duplication of the remaining mutant allele via polyploidization. Several tumors contained multiple copies of BRCA1 and BRCA2 genes without relative copy number changes, implying that loss of wild-type alleles is executed by alternative mechanisms such as mitotic recombination, non-disjunctional chromosomal loss with or without reduplication, or by gene conversion. A paradoxical relative copy number gain of the mutant allele was evident in three BRCA1 tumors (18%), which could be of biological relevance if a dominant negative or gain-of-function model was ascribed for certain BRCA1 mutants. Our results indicate that complex genetic alterations are operational at the BRCA1 and BRCA2 loci in tumors from genetically predisposed individuals.     

Identification of abrogated pathways in fallopian tube epithelium from BRCA1 mutation carriers

The discovery of occult invasive and intra-epithelial tubal carcinomas in BRCA1 mutation carriers undergoing prophylactic surgery has implicated the fallopian tube epithelium as the source of serous cancer. However, little is known of the early molecular events of serous oncogenesis, or why cancers in BRCA1 mutation carriers are found preferentially in tissues which are responsive to reproductive hormones. We hypothesize that molecular alterations present in morphologically normal tubal epithelium from BRCA1 heterozygotes reflect the earliest events in serous carcinogenesis and may be markers of increased cancer risk as well as targets for risk reduction. Genetic profiling of microdissected tubal epithelium from histologically normal BRCA1 mutation carriers and controls was performed. We sought to define a signature which differentiated BRCA1 mutant tubal epithelium from women with low risk of developing ovarian cancer. Molecular differences between the follicular and luteal phases were prominent and, by using filtering techniques and a two-way ANOVA without a False Discovery Rate correction, we identified 440 probe sets with a more than two-fold change in gene expression related to BRCA1 mutation status. Using gene ontology and known associations to cancer pathways, we selected five genes for further analysis by qPCR and immunohistochemistry, and were able to demonstrate statistically significant differentiation of BRCA1 and control cases in an independent set of cases. The altered expression profiles in histologically normal tubal epithelium from BRCA1 heterozygotes suggest that these cells may respond differently to microenvironmental stresses.     

Absence of CCND1 gene amplification in breast tumours of BRCA1 mutation carriers.

BACKGROUND/AIMS: It was recently reported that significantly fewer breast tumours of BRCA1 mutation carriers overexpressed cyclin D1 and HER2 protein than tumours of age matched breast cancer cases unselected for family history. This study aimed to examine the genetic basis of this reduction by determining the frequency of tumours within this cohort showing DNA amplification of these genes. METHODS: Paraffin wax embedded sections of breast tumours from BRCA1 mutation carriers and age, grade, histological type, and tumour size matched non-familial controls that had previously been stained for cyclin D1 and HER2 protein overexpression were analysed for CCND1 and HER2 gene amplification using fluorescence in situ hybridisation. RESULTS: CCND1 amplification was detected in none of the 30 tumours of the BRCA1 mutation carriers and in 19 of 74 tumours of the matched controls. Of those samples previously determined to overexpress the HER2 protein, HER2 amplification was detected in one of three tumours from BRCA1 mutation carriers and in 13 of 17 tumours of the age matched non-familial cases. CONCLUSION: None of the tumours of BRCA1 mutation carriers showed CCND1 amplification and only one tumour showed HER2 amplification. In contrast, a large proportion of cyclin D1 and HER2 overexpression in tumours of non-familial breast cancer cases could be accounted for by amplification of these genes. These data suggest that breast tumorigenesis in BRCA1 mutation carriers occurs by a molecular mechanism distinct from that of age matched non-familial cases.