Abstract 2735: Diagnosis of prostate cancer without tumor cells using differentially expressed genes in the tumor microenvironment

Abstract

Over one million prostate biopsies are performed in the U.S. every year. However, pathology examination is not definitive in a significant percentage of cases due to missing the tumor or equivocal structures. Given that the tissue near tumors will experience expression changes, biopsies could reveal the presence of a nearby tumor even if the biopsy contains no tumor. In order to identify reliable examples of such genes we compared gene expression profiles (Affymetrix U133plus2) from 15 volunteer biopsy specimens to 13 specimens containing largely tumor-adjacent stroma. More than a thousand significant expression changes were found and thereafter filtered to eliminate possible aging-related genes and genes also expressed at detectable levels in tumor cells. Classifiers were constructed based on 114 unique candidate genes (131 Affymetrix probe sets) and tested on 380 independent cases, including 255 tumor-bearing cases, 125 nontumor cases (normal biopsies, normal autopsies, remote stroma as well as pure tumor adjacent stroma). The classifier predicted the tumor status of patients with an average accuracy of 97.4% (sensitivity = 98.0% and specificity = 89.7%). These results indicate that the prostate cancer microenvironment exhibits reproducible changes useful for detecting “presence of tumor”.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2735.