Inherited loss-of-function mutations in the tumor suppressor genes BRCA1, BRCA2, and multiple other genes predispose to high risks of breast and/or ovarian cancer. Cancer-associated inherited mutations in these genes are collectively quite common, but individually rare or even private. Genetic testing for BRCA1 and BRCA2 mutations has become an integral part of clinical practice, but testing is generally limited to these two genes and to women with severe family histories of breast or ovarian cancer. To determine whether massively parallel, "next-generation" sequencing would enable accurate, thorough, and cost-effective identification of inherited mutations for breast and ovarian cancer, we developed a genomic assay to capture, sequence, and detect all mutations in 21 genes, including BRCA1 and BRCA2, with inherited mutations that predispose to breast or ovarian cancer. Constitutional genomic DNA from subjects with known inherited mutations, ranging in size from 1 to >100,000 bp, was hybridized to custom oligonucleotides and then sequenced using a genome analyzer. Analysis was carried out blind to the mutation in each sample. Average coverage was >1200 reads per base pair. After filtering sequences for quality and number of reads, all single-nucleotide substitutions, small insertion and deletion mutations, and large genomic duplications and deletions were detected. There were zero false-positive calls of nonsense mutations, frameshift mutations, or genomic rearrangements for any gene in any of the test samples. This approach enables widespread genetic testing and personalized risk assessment for breast and ovarian cancer.nherited mutations in BRCA1 and BRCA2 predispose to high risks of breast and ovarian cancer. Lifetime risks of breast cancer are as high as 80% among women with mutations in these genes, and lifetime risks of ovarian cancer are greater than 40% for carriers of BRCA1 mutations and greater than 20% for carriers of BRCA2 mutations (1). Inherited mutations in the Fanconi anemia genes BRIP1 (FANCJ) and PALB2 (FANCN) are associated with 20-50% lifetime risks of breast cancer (2, 3). Inherited mutations in TP53, PTEN, STK11, and CDH1 are associated with moderate to very high risks of breast cancer in the context of Li-Fraumeni syndrome, Cowden syndrome, Peutz-Jeughers syndrome, and hereditary diffuse gastric cancer syndrome, respectively (4, 5, 6, 7). Inherited mutations in several of the genes responsible for hereditary nonpolyposis colon cancer and endometrial cancer are also associated with elevated risks of ovarian cancer (8).Genetic testing for BRCA1 and BRCA2 mutations has become an integral part of clinical practice for women with severe family histories of breast or ovarian cancer, whether newly diagnosed or still clinically asymptomatic. However, as many as 50% of breast cancer patients with inherited mutations in BRCA1 and BRCA2 do not have close relatives with breast or ovarian cancer because their mutation is paternally inherited, the family is small, and by chance no sisters or paternal au...