Differences in the characteristics of families with BRCA1 and BRCA2 mutations in Israel

Prevalence of Germline BRCA1/2 Variants in Ashkenazi and Non-Ashkenazi Prostate Cancer Populations: A Systematic Review and Meta-Analysis

BACKGROUND AND AIMS

International guidelines recommend testing BRCA2 in men with prostate cancer, due to the presence of a strong association with this gene. Some ethnicities present disparities in genetic distribution for the relation with specific founder variants. Ashkenazi Jewish people are, importantly, at high risk of breast cancer for their inherited cluster with germline BRCA1/2 variants. However, in Ashkenazi men with prostate cancer, the prevalence of BRCA1 and/or BRCA2 is not well defined. We assessed the frequency of these variants in Ashkenazi vs. non-Ashkenazi men with prostate cancer. Materials and Methods: In accord with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement, we revised all germline BRCA variants reported in MEDLINE from 1996 to 2021 in Ashkenazi and non-Ashkenazi men with prostate cancer. Results: Thirty-five original studies were selected for the analysis. Among populations from Israel and North America, Ashkenazi Jewish men presented higher prevalence of BRCA1 variants [0.9% (0.4-1.5) vs. 0.5% (0.2-1.1), p = 0.09] and a lower prevalence of BRCA2 variants [1.5% (1.1-2.0) vs. 3.5% (1.7-5.9), p = 0.08] in comparison to the non-Ashkenazi population. Conclusions: Since germline BRCA1 variants are more prevalent and BRCA2 variants are less prevalent in PCa patients of Ashkenazi Jewish ethnicity in comparison to non-Ashkenazi patients, prostate cancer genetic screening in Ashkenazi men should not be restricted to the BRCA2 gene.

Genotype-Phenotype Correlations by Ethnicity and Mutation Location in BRCA Mutation Carriers

The genotype-phenotype correlations of the specific BRCA1 and BRCA2 mutations in multi-ethnic populations in USA have not yet been fully investigated. This study was designed to evaluate the effects of ethnicity at specific mutation locations and breast/ovarian cancer phenotypes. Our cohort included 445 women with different ethnic backgrounds who underwent BRCA genetic testing between 1997 and 2010. Known clinical and pathologic characteristics were compared with Chi-Square Analysis or Fisher's Exact test as appropriate. The three most common mutation locations in BRCA1 (exons 2, 11, and 20) and BRCA2 (exons 10, 11, and 25) genes were chosen. Prevalence of BRCA1 exon 2 mutations were significantly higher in Ashkenazi Jewish (AJ) women compared to Caucasians (41% versus 15%; p = 0.001). Similarly, AJ women with breast cancer were more likely to have BRCA1 exon 2 mutation (47% positivity in AJ women versus 0-12.5% positivity in other ethnicities; p = 0.004). Women carrying the exon 20 BRCA1 mutation had the highest probability of having combined breast and ovarian cancers compared to women carrying other exon mutations (p = 0.05). The median age at initial cancer diagnosis, phenotypic features of breast cancer tumors, and overall survival did not vary significantly by ethnicity or mutation location. Our data suggest that ethnicity does not affect age of onset, overall survival or confer different risks of breast and ovarian cancer development in BRCA carriers. These results also suggest that women carrying the exon 20 BRCA1 mutation may warrant mutation-specific counseling and be more aggressively managed for risk reduction.

BRCA1 and BRCA2 mutations in ethnic Lebanese Arab women with high hereditary risk breast cancer

PURPOSE

Breast cancer is the most common malignancy among women in Lebanon and in Arab countries, with 50% of cases presenting before the age of 50 years.

METHODS

Between 2009 and 2012, 250 Lebanese women with breast cancer who were considered to be at high risk of carrying BRCA1 or BRCA2 mutations because of presentation at young age and/or positive family history (FH) of breast or ovarian cancer were recruited. Clinical data were analyzed statistically. Coding exons and intron-exon boundaries of BRCA1 and BRCA2 were sequenced from peripheral blood DNA. All patients were tested for BRCA1 rearrangements using multiplex ligation-dependent probe amplification (MLPA). BRCA2 MLPA was done in selected cases.

RESULTS

Overall, 14 of 250 patients (5.6%) carried a deleterious BRCA mutation (7 BRCA1, 7 BRCA2) and 31 (12.4%) carried a variant of uncertain significance. Eight of 74 patients (10.8%) aged ≤40 years with positive FH and only 1 of 74 patients (1.4%) aged ≤40 years without FH had a mutated BRCA. Four of 75 patients (5.3%) aged 41-50 years with FH had a deleterious mutation. Only 1 of 27 patients aged >50 years at diagnosis had a BRCA mutation. All seven patients with BRCA1 mutations had grade 3 infiltrating ductal carcinoma and triple-negative breast cancer. Nine BRCA1 and 17 BRCA2 common haplotypes were observed.

CONCLUSION

Prevalence of deleterious BRCA mutations is lower than expected and does not support the hypothesis that BRCA mutations alone cause the observed high percentage of breast cancer in young women of Lebanese and Arab descent. Studies to search for other genetic mutations are recommended.

An inherited NBN mutation is associated with poor prognosis prostate cancer

BACKGROUND

To establish the contribution of eight founder alleles in three DNA damage repair genes (BRCA1, CHEK2 and NBS1) to prostate cancer in Poland, and to measure the impact of these variants on survival among patients.

METHODS

Three thousand seven hundred fifty men with prostate cancer and 3956 cancer-free controls were genotyped for three founder alleles in BRCA1 (5382insC, 4153delA, C61G), four alleles in CHEK2 (1100delC, IVS2+1G>A, del5395, I157T), and one allele in NBS1 (657del5).

RESULTS

The NBS1 mutation was detected in 53 of 3750 unselected cases compared with 23 of 3956 (0.6%) controls (odds ratio (OR)=2.5; P=0.0003). A CHEK2 mutation was seen in 383 (10.2%) unselected cases and in 228 (5.8%) controls (OR=1.9; P<0.0001). Mutation of BRCA1 (three mutations combined) was not associated with the risk of prostate cancer (OR=0.9; P=0.8). In a subgroup analysis, the 4153delA mutation was associated with early-onset (age ≤ 60 years) prostate cancer (OR=20.3, P=0.004). The mean follow-up was 54 months. Mortality was significantly worse for carriers of a NBS1 mutation than for non-carriers (HR=1.85; P=0.008). The 5-year survival for men with an NBS1 mutation was 49%, compared with 72% for mutation-negative cases.

CONCLUSION

A mutation in NBS1 predisposes to aggressive prostate cancer. These data are relevant to the prospect of adapting personalised medicine to prostate cancer prevention and treatment.

Factors influencing uptake and timing of risk reducing salpingo-oophorectomy in women at risk of familial ovarian cancer: a competing risk time to event analysis

OBJECTIVE

To evaluate factors affecting uptake of risk-reducing salpingo-oophorectomy (RRSO) over time in women at high-risk of familial ovarian cancer.

DESIGN

Prospective observational cohort.

SETTING

Tertiary high-risk familial gynaecological cancer clinic.

POPULATION/SAMPLE

New clinic attendees between March 2004 and November 2009, fulfilling the high-risk criteria for the UK Familial Ovarian Cancer Screening Study.

METHODS

Risk management options discussed included RRSO and ovarian surveillance. Outcome data were analysed from a bespoke database. The competing risk method was used to model the cumulative incidence function (CIF) of RRSO over time, and the sub-hazard ratio (SHR) was used to assess the strength of the association of variables of interest with RRSO. Gray's test was used to evaluate the difference in CIF between two groups and multivariable competing risk regression analysis was used to model the cumulative probabilities of covariates on the CIF.

RESULTS

Of 1133 eligible women, 265 (21.4%) opted for RRSO and 868 (69.9%) chose screening. Women undergoing RRSO were older (49 years, interquartile range 12.2 years) than those preferring screening (43.4 years, interquartile range 11.9 years) (P < 0.0005). The CIF for RRSO at 5 years was 0.55 (95% CI 0.45-0.64) for BRCA1/2 carriers and 0.22 (95% CI 0.19-0.26) for women of unknown mutation status (P < 0.0001); 0.42 (95% CI 0.36-0.47) for postmenopausal women (P < 0.0001); 0.29 (95% CI 0.25-0.33) for parity ≥1 (P = 0.009) and 0.47 (95% CI 0.39-0.55) for a personal history of breast cancer (P < 0.0001). Variables of significance from the regression analysis were: a BRCA1/2 mutation (SHR 2.31, 95% CI 1.7-3.14), postmenopausal status (SHR 2.16, 95% CI 1.62-2.87)) and a personal history of breast cancer (SHR 1.5, 95% CI 1.09-2.06).

CONCLUSIONS

Decision-making is a complex process and women opt for surgery many years after initial risk assessment. BRCA carriers, postmenopausal women and women who had breast cancer are significantly more likely to opt for preventative surgery.

Double heterozygosity in the BRCA1 and BRCA2 genes in the Jewish population

BACKGROUND

The frequency and characteristics of disease in individuals who concomitantly harbor pathogenic mutations in both BRCA1 and BRCA2 genes are not established.

MATERIALS AND METHODS

Data were collected from the database of Clalit Health Services National Familial Cancer Consultation Service. Probands referred to this clinical service and their family members are routinely tested for the three Jewish founder mutations (BRCA1: 185delAG, 5382insC, BRCA2: 6174delT). In addition, carriers identified in a population-based cohort of all cases diagnosed with breast cancer in Israel in 1987-1988 allowed the estimation of the population frequency of this phenomenon.

RESULTS

In the clinic-based series of 1191 carriers of mutations in BRCA1 or BRCA2 belonging to 567 families, 22 males and females (1.85%) from 17 different families (3.0%) were found to harbor two different mutations. These included 18 individuals (1.51%) who concomitantly carried the 185delAG BRCA1 and the 6174delT BRCA2 mutations and four individuals (0.34%) who carried the 5382insC BRCA1 and the 6174delT mutations. All individuals were heterozygote carriers and none had a double mutation of both founder mutations in the BRCA1 gene itself. Seven of the 16 double carrier women (46.7%) had a personal history of breast carcinoma, diagnosed at a mean age of 44.6, compared with 372/926 (40.2%) carriers of a single mutation diagnosed with a mean age at diagnosis of 48.1 [odds ratio (OR)=1.3, 95% confidence interval (CI) 0.4-4.0]. One case (6.7%) had a personal history of ovarian carcinoma diagnosed at the age of 53 compared with 55/926 (5.9%) of the women with single mutation (OR=1.1, CI=0.2-7.6). The frequency of double mutations in the population-based national breast cancer cohort was 2.2% of all carriers, and 0.3% of all breast cancer cases in the Ashkenazi population in the cohort. The mean age at diagnosis of breast cancer was younger in the carriers of two mutations.

CONCLUSION

Double carriers of mutations in the BRCA genes are rare and seem to be carrying a similar probability of developing breast and ovarian cancers as carriers of single mutations.

Risk stratification in cancer predisposition syndromes: lessons learned from novel molecular developments in Li-Fraumeni syndrome

Germ-line mutations in specific genes predispose family members to cancer. Prediction of the exact tumor type and timing of cancer initiation is fundamental to the development of management strategies for these individuals. Recent advances in our understanding of the general processes that control cancer initiation may enable us to tailor more precise risk stratification. This, in turn, will lead to more effective early detection strategies, which would result in more favorable clinical outcomes. In this review, we highlight the steps and methods used to reach this futuristic model.