Peritoneal washing is an adequate source for somatic BRCA1/2 mutation testing in ovarian malignancies.

Genetic screening for BRCA mutations should be offered to all women diagnosed with epithelial ovarian, fallopian tube, and/or peritoneal cancers given the implications for treatment options and cancer risk assessments. Yet, while germline breast cancer susceptibility gene 1 (BRCA1) and breast cancer susceptibility gene 2 (BRCA2) testing is commonly performed, BRCA1/2 somatic mutations testing is rather challenging since the poor quality of DNA extracted from formalin fixed paraffin embedded (FFPE) samples can significantly impair this process. Peritoneal lavage is routinely performed in surgeries of suspected ovarian malignancies. We have analyzed fresh tumor, peritoneal lavage and blood samples from ten patients and we have found an excellent agreement (88%) between fresh tumor and peritoneal lavage for BRCA mutation testing. Importantly, 112 of the 114 genomic alterations detected in fresh tumor samples were also found in peritoneal lavage fluids. Our data suggest that peritoneal washings can indeed streamline BRCA genes mutation testing procedures.