Immunohistochemical expression of retinoblastoma and p53 tumor suppressor genes in prostatic intraepithelial neoplasia: comparison with prostatic adenocarcinoma and benign prostate

• Published in: Modern pathology Vol. 11; no. 3; p. 247
• Main Authors: Tamboli, P, Amin, M B, Xu, H J, Linden, M D
• Format: Journal Article
• Language: English
• Published: United States 01.03.1998
• Subjects: Adenocarcinoma - chemistry; Adenocarcinoma - pathology; Biomarkers, Tumor - analysis; Biomarkers, Tumor - biosynthesis; Gene Expression; Genes, p53 - genetics; Genes, Retinoblastoma - genetics; Humans; Immunohistochemistry; Male; Neoplasm Staging; Prostate - chemistry; Prostate - metabolism; Prostate - pathology; Prostatic Hyperplasia - pathology; Prostatic Intraepithelial Neoplasia - chemistry; Prostatic Intraepithelial Neoplasia - genetics; Prostatic Intraepithelial Neoplasia - pathology; Prostatic Neoplasms - chemistry; Prostatic Neoplasms - genetics; Prostatic Neoplasms - pathology; Retinoblastoma Protein - analysis; Retrospective Studies; Tumor Suppressor Protein p53 - analysis
• ISSN: 0893-3952

Mutational alterations involving the p53 and retinoblastoma (RB) tumor suppressor genes are implicated in the oncogenesis of a variety of tumors. Their role in the pathogenesis of prostatic adenocarcinoma remains to be fully elucidated, and their detection in high-grade prostatic intraepithelial neoplasia (HG-PIN) has not been closely examined. We studied the immunohistochemical expression of RB and p53 proteins in HG-PIN, benign prostate, and prostatic adenocarcinoma from 25 radical prostatectomy specimens. Formalin-fixed, paraffin-embedded tissue sections pretreated with antigen retrieval in citrate buffer were stained with anti-RB antibody RB-WL-1 and anti-p53 antibody DO-7. RB immunoreactivity was present in all of the cases in the foci of HG-PIN, benign prostate, and prostatic adenocarcinoma. Mutant p53 protein was detected in 56% of HG-PIN, 72% of prostatic adenocarcinomas, and 20% of benign prostatic glands. A multivariate analysis of variance showed an overall difference in p53 immunoreactivity between HG-PIN, benign prostate, and prostatic adenocarcinoma (P < .001). There was a statistically significant difference between immunoreactivity of the benign prostate and of HG-PIN (P < .001) and between the immunoreactivity of benign prostate and prostatic adenocarcinoma (P < .001). The immunoreactivities of HG-PIN and prostatic adenocarcinoma were not statistically different (P = .3). These data suggest that RB loss might not play a role in initiation of all cases of prostatic adenocarcinoma. The p53 immunoreactivity in HG-PIN was significantly different from that found in benign prostate and was similar to that of prostatic adenocarcinoma. This is in keeping with the putative premalignant character of HG-PIN.