Abstract 3669: Assessing the genetic heterogeneity of localized, multifocal prostate cancer via cell-free DNA

Abstract

Abstract At the time of diagnosis, it is common to find multiple spatially distinct foci within a single prostate gland in men with prostate cancer. Recent studies evaluating the genetic heterogeneity of localized, multifocal prostate cancers through whole-genome sequencing and whole-exome sequencing have only recently been described. These tumors were highly heterogeneous for single-nucleotide variants, copy number alterations, and genomic rearrangements. One exciting use of cfDNA is its potential ability to simultaneously capture all genetically distinct tumor subclones. Currently, the degree to which a cfDNA sample is representative of the entire genetic landscape of localized prostate cancer is unknown. The objective of this study is to determine if somatic mutations identified in tumor tissue are detectable in cfDNA. Tumor tissue and blood samples have been collected from twenty-nine patients undergoing radical prostatectomy. Samples from fourteen patients have already been subjected to whole-exome sequencing with a target sequencing depth of 200X (HiSeq 4000). Preliminary analyses indicate that tumor foci within a single prostate gland in an individual are genetically heterogeneous. Further analysis of mutational concordance between tumor tissue DNA and cfDNA along with clinical data will be performed. Citation Format: Emmalyn Chen, Clinton L. Cario, Lancelote Leong, Karen Lopez, Jeffry P. Simko, Peter R. Carroll, Caroline Tai, John S. Witte. Assessing the genetic heterogeneity of localized, multifocal prostate cancer via cell-free DNA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3669.