Breast and ovarian cancer penetrance of mutations among Hong Kong women.

Germline mutations in and () are associated with increased risk of breast and ovarian cancer. The penetrance of breast and ovarian cancer in mutation carriers has been well characterized in Caucasian but not in Asian. Two studies have investigated the breast cancer risk in Asian women with mutations, and no published estimates are available for ovarian cancer. Therefore, we estimated the age-specific cumulative risk of -associated breast and ovarian cancer in Chinese women. From Jan 2007 to Nov 2015, the Hong Kong Hereditary Breast Cancer Family Registry identified 1635 families with hereditary breast-ovarian cancer. Among probands in these families, 66 had mutations, 84 had mutations, and 1,485 tested negative for mutations. Using the female first-degree relatives of these probands, we estimated the risk of breast and ovarian cancer using a modified marginal likelihood approach. Estimates of breast cancer penetrance by age 70 were 53.7% (95% CI 34.5-71.6%) for mutation carriers and 48.3% (95% CI 31.8-68.5%) for . The estimated risk of ovarian cancer by age 70 was 21.5% and 7.3% for Chinese women carrying or mutation respectively. A meta-analysis of available studies in Asian women revealed pooled estimates of breast cancer risk by age 70 of 44.8% (95% CI 33-57.2%) and 40.7% (95% CI 31.3-50.9%) for and mutation carriers respectively. These data suggest that -associated breast cancer risk for Chinese women is similar to that for Caucasian women, although -associated ovarian cancer risks are lower for Chinese women.