Rates of risk-reducing surgery in Israeli BRCA1 and BRCA2 mutation carriers.

The frequency of BRCA1 and BRCA2 mutations is higher in Israel than in almost all other countries. One strategy to reduce the burden of hereditary breast and ovarian cancers is to offer genetic testing followed by risk-reducing surgery (mastectomy and salpingo-oophorectomy) for mutation carriers. The extent to which Israeli women who carry mutations undergo these surgeries is not well characterized. Israeli women who are BRCA1 or BRCA2 mutation carriers and followed at a single high-risk clinic were asked to complete a questionnaire detailing their clinical histories at the time of genetic results disclosure and a follow-up questionnaire was completed 18 or more months thereafter. A total of 205 mutation carriers completed the questionnaires. Of 170 women with no cancer history, 84 (49%) had a risk-reducing bilateral salpingo-oophorectomy and 22 (13%) had a risk-reducing mastectomy. Five of 35 (14.3%) women with breast cancer opted for contralateral mastectomy. Approximately one half of Israeli women with a BRCA1 or BRCA2 mutation opt for risk-reducing oophorectomy, but the rate of risk-reducing mastectomy is only 13%.

Functional variant of KLOTHO: a breast cancer risk modifier among BRCA1 mutation carriers of Ashkenazi origin.

Klotho is a transmembrane protein that can be shed and act as a circulating hormone and is a putative tumor suppressor in breast cancer. A functional variant of KLOTHO (KL-VS) contains two amino acid substitutions F352V and C370S and shows reduced activity. Germ-line mutations in BRCA1 and BRCA2 substantially increase lifetime risk of breast and ovarian cancers. Yet, penetrance of deleterious BRCA1 and BRCA2 mutations is incomplete even among carriers of identical mutations. We examined the association between KL-VS and cancer risk among 1115 Ashkenazi Jewish women: 236 non-carriers, 631 BRCA1 (185delAG, 5382insC) carriers and 248 BRCA2 (6174delT) carriers. Among BRCA1 carriers, heterozygosity for the KL-VS allele was associated with increased breast and ovarian cancer risk (hazard ratio 1.40, 95% confidence intervals 1.08-1.83, P=0.01) and younger age at breast cancer diagnosis (median age 48 vs 43 P=0.04). KLOTHO and BRCA2 are located on 13q12, and we identified linkage disequilibrium between KL-VS and BRCA2 6174delT mutation. Studies in breast cancer cells showed reduced growth inhibitory activity and reduced secretion of klotho F352V compared with wild-type klotho. These data suggest KL-VS as a breast and ovarian cancer risk modifier among BRCA1 mutation carriers. If validated in additional cohorts, the presence of KL-VS may serve as a predictor of cancer risk among BRCA1 mutation carriers.

Evaluation of a candidate breast cancer associated SNP in ERCC4 as a risk modifier in BRCA1 and BRCA2 mutation carriers. Results from the Consortium of Investigators of Modifiers of BRCA1/BRCA2 (CIMBA).

BACKGROUND: In this study we aimed to evaluate the role of a SNP in intron 1 of the ERCC4 gene (rs744154), previously reported to be associated with a reduced risk of breast cancer in the general population, as a breast cancer risk modifier in BRCA1 and BRCA2 mutation carriers. METHODS: We have genotyped rs744154 in 9408 BRCA1 and 5632 BRCA2 mutation carriers from the Consortium of Investigators of Modifiers of BRCA1/2 (CIMBA) and assessed its association with breast cancer risk using a retrospective weighted cohort approach. RESULTS: We found no evidence of association with breast cancer risk for BRCA1 (per-allele HR: 0.98, 95% CI: 0.93-1.04, P = 0.5) or BRCA2 (per-allele HR: 0.97, 95% CI: 0.89-1.06, P = 0.5) mutation carriers. CONCLUSION: This SNP is not a significant modifier of breast cancer risk for mutation carriers, though weak associations cannot be ruled out.