Abstract 254: Expression of the putative stem cell marker CD44 in prostate biopsies correlates with Gleason score in radical prostatectomies in patients with prostate cancer.

Abstract

Abstract AIM: Prostate cancer is one of the leading causes of death among male oncology patients. There is growing evidence to support the hypothesis that cancer cells in the prostate are of stem cell origin. In this study we used CD44, as one of the most promising putative stem cell markers, to evaluate the prevalence of prostate cancer cells with stem cell like features in prostate biopsies and in radical prostatectomy specimens. We tested both types of specimen for the existence of a correlation between the expression of CD44 and commonly used prostate cancer prognostic factors such as Gleason grade, pathological stage (pT) according to TNM, patient age and preoperative plasma PSA levels. M&M: Formalin fixed paraffin embedded tissue samples from fifty two prostate biopsies and matched radical prostatectomy specimens were retrieved from the archives of the Pathology Department at the City Hospital, Poznan, Poland or from a collection of cases sent for consultation in the private laboratory of one of the authors (JB). Immunohistochemistry was performed on sections from all paraffin blocks using an anti-CD44 primary antibody (Abcam) according to the manufacturer's protocol. Using an OLYMPUS BX41 microscope, we counted at least 100 cancer cells from core biopsies and 500 cancer cells from radical prostatectomy specimens. Only cells with clearly visible membranous staining at 10x magnification were called positive for the expression of CD44. The percentage of cancer cells expressing CD44 was used for further analysis. The statistical analysis was based on Spearman and Person correlations performed in Microsoft Office Excel 2007. RESULTS: CD44 positive cancer cells were identified in forty three prostate biopsies (82%) and forty seven radical prostatectomy specimens (90%). There was a positive correlation between the expression of CD44 in cancer cells from prostate biopsies and in radical prostatectomy specimens. We also observed a negative correlation between CD44 expression in cancer cells and Gleason score, both in prostate biopsies and in radical prostatectomy material. When other clinical data were analysed, such as patient age, preoperative PSA serum levels or tumour stage (pT), only the first parameter was found to correlate positively with CD44 expression in prostate biopsies. CONCLUSION: To the best of our knowledge this study showed for the first time, that the level of CD44 expression in prostate biopsies correlates with that observed in matched radical prostatectomy specimens. Additionally, we confirmed the results of other authors which show that the percentage of CD44 expressing cancer cells in prostate biopsies negatively correlates with Gleason grade of tumours, both in prostate biopsies and in radical prostatectomy material. Citation Format: Konstanty Korski, Anna Malicka, Jan Breborowicz. Expression of the putative stem cell marker CD44 in prostate biopsies correlates with Gleason score in radical prostatectomies in patients with prostate cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 254. doi:10.1158/1538-7445.AM2013-254