Genomic characterization of ductal adenocarcinoma of the prostate.

5030Background: Ductal prostate cancer (dPC) is a rare prostate cancer variant associated with poor outcomes. Prior small case series have documented that dPCs may be enriched for alterations in DNA damage repair (DDR) pathway genes and activation of WNT- and PI3K-pathways. To expand these findings, we formed a multicenter collaboration with the goal to provide a comprehensive overview of the spectrum of mutations associated with dPC. Methods: We assembled three case series across multiple institutions in the United States and Canada. All patients carried a diagnosis of dPC, and histopathologic classification was confirmed by an expert genitourinary pathologist at each respective institution. All tumor tissue was sequenced on a targeted next-generation sequencing (NGS) assay, UW-OncoPlex, according to previously published methods. Tumor samples were acquired from men with dPC treated at the University of Washington/Seattle Cancer Care Alliance (N = 21), Johns Hopkins Hospital (N = 21) and University of Ca...