Abstract 3637: Loss of prostate derived Ets (E-twenty six) transcription factor (PDEF) predicts patients at the highest risk of metastatic prostate cancer

Abstract

Abstract PSA has ability to detect prostate cancer (CaP) at an early stage, but many CaP tumors are slow to progress, and many patients are overtreated for a disease that will not become life-threatening. Since there remains no reliable way to distinguish indolent from aggressive disease, doctors who advise and patients on active surveillance worry about progression to incurable disease. Therefore, new prognostic tools must be developed to identify patients with potentially metastatic, life threatening CaP. Prostate derived Ets transcription factor (PDEF) has shown to be a master negative regulator of transcriptional networks controlling migration and invasion in many cancer tissues, including CaP. Therefore we studied the expression of PDEF in radical prostatectomy specimens to determine retrospectively whether PDEF expression is predictive of clinical outcome. Patients’ tumor PDEF expression was determined by immunohistochemical staining of a 724 patient tissue microarray (TMA). CaP patients were stratified into groups based on PDEF expression (high, mid, low, null) and a Cox proportional hazards model was used to compare clinical outcomes. Univariate analysis showed that loss of PDEF expression significantly increased risk of metastatic disease (HR = 5.38, PDEF mid; to HR = 43.48, PDEF null; p=0.0059), although it did not correlate with incidence of biochemical failure detected using the American Urological Association (AUA) or National Comprehensive Cancer Network (NCCN) definitions. This result was confirmed in the Kaplan-Meier survival analysis that showed that patients whose CaP were PDEF low/null had significantly shorter metastases-free survival (p=0.0151). Multivariate analysis also demonstrated CaP with low/null PDEF expression were associated with increased risk of developing metastatic disease (HR = 6.21/10.53), although it was not statistically significant, in part due to the low incidence of patients with metastatic disease in the TMA. Therefore, we studied PDEF and vimentin (stem-like marker, repressed by PDEF) tumor expression in a cohort of patients matched for Gleason score, stage, age, and follow-up who developed metastatic disease versus those who did not. Patients that developed metastatic disease had a significantly lower PDEF (3.9 vs 1.7, p<0.0001) and higher vimentin (0.43 vs. 4.1, p<0.0001) expression compared to matched controls. We propose that intact PDEF expression in CaP can be used to distinguish patients who are suitable for active surveillance from those who require aggressive treatment. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 3637. doi:1538-7445.AM2012-3637