Germline Testing In Hereditary Cancer Genes Subsequent To The Identification Of Mutations In Tumor Specimens

1527 Background: Molecular profiling of tumors is crucial in identifying targeted therapies. Secondarily, tumor DNA sequencing has the potential to reveal germline mutations leading to the diagnosis of a hereditary cancer predisposition. We sought to determine the frequency and clinical significance of germline testing performed at one laboratory subsequent to tumor profiling. Methods: Retrospective review of a laboratory database revealed 74 germline test orders following identification of mutations in tumor specimens from 54 patients. Age at cancer diagnosis, family history and a description of the patient’s tumor including associated somatic mutations were obtained from test requisitions. Germline targeted sequencing was performed with DNA isolated from blood or saliva. Pathogenic mutations identified in hereditary cancer predisposition genes were included for analysis. Results: Ten of 74 (13%) tumor mutations were confirmed in the germline. The remaining mutations are presumed to be somatic. Mutations...