Immunohistochemical Identification of Cancer Stem Cells in Human Prostate Carcinomas
Ming Yin, Jasmine Mays, Randall Falls. Brody School of Medicine at East Carolina University, Greenville, NC
Background: Recent evidence indicates that cancer stem cells are responsible for tumor initiation and recurrence. Development of prostatic carcinoma (Pca) resistant to androgen-deprivation therapy has led to hypothesis that Pca contains a subpopulation of stem cells that do not express androgen receptor. Previous in vitro and in vivo studies using cell lines/xenograft tumor models provided compelling evidence that CD44 expression is associated with stem/progenitor cells. CD133 has been used to identify stem cells from leukemia and brain tumors. The purpose of this study is to identify the cancer stem cells in benign and malignant prostatic tissues using putative markers and correlate their expression with grades of tumor differentiation.
Design: Forty eight paraffin-embedded prostatectomy specimens with adenocarcinomas of different Gleason scores were randomly collected for immunohistochemical stains with putative stem cell markers CD44 and CD133. A composite score was calculated as a product of the staining intensity (0 – 3+) multiplying the percentage of positive cells.
Results: The basal cells of benign glands, which are known to have stem cell-like properties without androgen receptors and function as the progenitors of the secretory epithelial cells, are positive for CD44. Benign glandular epithelial cells and invasive carcinomas show a variable, small population of CD44-positive cells.
There was no statistical difference between benign and malignant glands of varying Gleason scores. Interestingly, high-grade prostatic intraepithelial neoplasia (HGPIN) demonstrate abundant epithelial expression of CD44. There was no CD133 staining seen in benign and neoplastic tissue.
Conclusions: CD44 positivity in basal cells confirms that CD44 identifies cells with stem cell-like properties. A small proportion of CD44-positive cells are present in benign and malignant components. Further characterization of these cells may lead to better understanding of tumorigenesis and targeted therapeutics. The study shows no relationship between the number of CD44-positive cells and tumor Gleason scores. The fact that larger numbers of HGPIN cells demonstrate CD44 expression warrants further studies.
Category: Genitourinary (including renal tumors)
Monday, March 19, 2012 1:00 PM
Poster Session II # 193, Monday Afternoon