BRCA1 and breast cancer: In an analysis of two population-based case-control studies involving 2013 women diagnosed with breast cancer before age 35 years and no family history and 225 affected women under the age of 45 years and a positive first-degree family history of breast cancer, Malone et al. found that 12% of women aged <45 years with a family history of breast cancer were carriers of BRCA1/2 mutations.