[1001] Expression of Stem Cell Markers EZH2 and Sox2 in Prostate Carcinomas

AV Ugolkov, LJ Eisengart, XJ Yang. Northwestern University, Chicago, IL

Background: A small population of tumor-initiating cells or cancer stem cells has been suggested to contribute to carcinogenesis, tumor relapse and chemoresistance. In prostate cancer, CD44+ and CD133+ cancer cells have been shown to have stem cell properties. To identify potential prostate stem cells, we conducted immunohistochemical (IHC) analysis of stem cell marker expression in benign prostate and prostatic adenocarcinoma.
Design: Immunohistochemistry was performed on a formalin-fixed, paraffin embedded tissue microarray (TMA) composed of high grade PIN, Gleason 3, 4 and 5 cancers, and benign prostate. Stains for CD44 and CD133, as well as embryonic stem cell markers Oct4, EZH2 and Sox2 were done. Positive staining was defined as 1+(<10%), 2+(10-50%), 3+(>50%). Statistical analysis was done with the Chi-Square test.
Results: We found CD44 staining in 97% and 72% of benign and malignant glands, respectively. CD133 staining was detected in a small fraction (4 of 67) of prostate carcinomas. Oct4 nuclear expression was strongly associated with benign glands but not prostate cancer (p<0.05). EZH2 1+ expression was found in 70% and 76% of benign and malignant glands, respectively. Sox2 1+ expression was found in 68% and 50% of benign and malignant glands, respectively. Moreover, 27 of 33 Sox2 1+ prostate adenocarinomas were also EZH2 1+. All of these were CD44+, suggesting that embryonic markers EZH2 and Sox2 can identify a minor subgroup of potential cancer stem cells within CD44 positive prostatic adenocarcinoma cells.
Conclusions: Our results demonstrate expression of progenitor cell marker CD44 but not CD133 in most benign and malignant prostate cells, and suggest that combined expression of embryonic stem cell markers EZH2 and Sox2 can identify potential stem cells as a minor (<10%) subgroup in CD44 positive prostatic adenocarcinoma.
Category: Genitourinary (including renal tumors)

Wednesday, March 24, 2010 1:00 PM

Poster Session VI # 118, Wednesday Afternoon


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