Expression of ezrin in prostatic intraepithelial neoplasia

Objectives. To study the protein expression and gene copy number of ezrin in a set of high-grade prostatic intraepithelial neoplasia (HGPIN) samples with concomitant prostate cancer. Ezrin is a cytoskeleton linker protein that is actively involved in regulating the growth and metastatic capacity of cancer cells. Methods. Nineteen HGPIN samples obtained from radical prostatectomy specimens were used for the study. Among them, 13 samples also contained invasive prostate cancer. The expression of ezrin was studied by immunohistochemistry. The same samples were also used for fluorescence in situ hybridization to study the gene copy number of ezrin. Results. Immunoreactivity for ezrin was absent or weak in benign prostatic epithelial cells. Weak or moderate immunostaining was detected in 11 of 13 prostate cancer specimens. However, the immunostaining was moderate or strong in all HGPIN samples. In addition, whenever HGPIN and prostate cancer were found in the same sample, the staining was always more intense in the HGPIN cells than in the cancer cells. No alteration was found in the gene copy number detected by fluorescence in situ hybridization. Conclusions. We have shown that ezrin is overexpressed in HGPIN and prostate cancer compared with adjacent benign prostatic epithelium. In addition, HGPIN has a greater expression level of ezrin compared with that of prostate cancer. Our results indicate that aberrant expression of ezrin might be involved in the pathogenesis of prostate cancer, and ezrin expression maybe useful for the diagnosis of HGPIN. UROLOGY 63: 609-612, 2004. (C) 2004 Elsevier Inc.