Immunohistochemical Localization of Insulin-Like Growth Factor Binding Proteins 2 and 3 in Prostate Tissue: Clinical Correlations

AbstractPurpose: The insulin-like growth factor system has recently been shown to have important mitogenic effects in the prostate. The system consists of 2 ligands: insulin-like growth factor types 1 and 2, which are potent mitogens for prostate cell growth, and 6 insulin-like growth factor binding proteins that modify the activity of these growth factors. Recently, changes in serum levels of insulin-like growth factor binding proteins 2 and 3 have been identified in prostate cancer patients but in vivo studies of these changes have not been previously reported.Materials and Methods: We performed immunohistochemical staining for insulin-like growth factor binding proteins 2 and 3 in areas of benign disease, prostatic intraepithelial neoplasia, and cancer from specimens obtained from 24 patients who underwent prostatectomy to determine changes in the quantity of these proteins with progression from the benign through the premalignant and into the malignant states. Quantification of the differences noted i...