Population attributes affecting the prevalence of BRCA mutation carriers in epithelial ovarian cancer cases in Israel

Objective. The objective was to evaluate the prevalence of BRCA1/2 mutations in selected categories of ovarian cancer patients in Israel. Methods. Blood samples and specimens of ovarian tumors were obtained in the course of a national case control study of women with ovarian cancer in Israel. Eight hundred ninety-six patients with epithelial ovarian cancer, 40 cases with nonepithelial ovarian cancer, and 68 with primary peritoneal cancer were tested for the BRCA mutations. Analysis of the three common BRCA mutations in Israel (185delAG, 5382insC in BRCA1, and 6174delT in BRCA2) was done using a multiplex polymerase chain reaction assay. A multivariate logistic regression model was used to assess the association of mutation carrier status and other factors (age, origin, family history, and clinical variables). Results. Of the 779 invasive epithelial ovarian cancer cases, 29.4% were mutation carriers. The prevalence of the mutations was higher among women below age 60 and in more advanced cases. The prevalence was low in mucinous tumors. There was almost a twofold excess of mutations among women with positive family history (45.7%), but still 26.5% of the family history negative cases were carriers. As expected, we found a higher rate of mutation carriers among the Ashkenazi group (34.2%) and 55% among Ashkenazi women with positive family history. No subjects born in North Africa were mutation positive. Conclusion. BRCA mutations are strongly associated with ovarian cancer and they are present in variable rates in distinct age, ethnic, and histopathologic categories.