The Mutational Spectrum Of Breast And Ovarian Tumors From Brca1 And Brca2 Mutation Carriers.

1510 Background: Individuals who carry one mutated copy of the BRCA1 or BRCA2 genes have elevated lifetime risks of breast and ovarian cancer. A number of studies have investigated the somatic mutational spectra of breast and ovarian tumors; however, BRCA1/2mutated tumors are underrepresented. Methods: Sixty-eight formalin-fixed paraffin embedded samples from BRCA1/2patients have been identified. Massively parallel sequencing using 48 gene capture is in process, whole exome sequencing of tumor and matched germline DNA is planned. Data are analyzed using a custom bioinformatics pipeline. Results: In analysis of data from the first 26 breast (4 BRCA1, 6 BRCA2) and ovarian (8 BRCA1, 8 BRCA2) tumors, the majority (23/26, 88%) had 0-2 variants in 48 cancer genes. Known deleterious TP53 mutations were the only variants identified in 2/4 BRCA1 and 2/6 BRCA2 breast tumors. Of those remaining, 2 BRCA1 and 1 BRCA2 breast tumors had no identified deleterious mutations. Two BRCA2 breast tumors with no TP53 mutations ...