COMPARATIVE-ANALYSIS OF MESSENGER-RNA AND PROTEIN EXPRESSION FOR EPIDERMAL GROWTH-FACTOR RECEPTOR AND LIGANDS RELATIVE TO THE PROLIFERATIVEINDEX IN HUMAN PROSTATE TISSUE

The expression of epidermal growth factor receptor (EGF-R), transformi ng growth factor alpha (TGF alpha), and epidermal growth factor (EGF) was evaluated in a series of prostate cancer (CaP; n = 55) and benign prostate hyperplasia (BPH; n = 44) specimens using immunocytochemistry (ICC) and Northern blotting. In situ hybridization (ISH), performed o n a subgroup of these specimens, proved to be a more informative techn ique for the assessment of messenger RNA (mRNA) in this heterogeneous tissue. A comparative analysis was made in relation to the proliferati ve index, assessed using the MIB-1 antibody, Elevated levels of EGF-R and TGF alpha, mRNA, and protein were observed in carcinoma cells comp ared with benign, secretory epithelium using in situ hybridization and immunocytochemistry. In carcinoma specimens evidence of an autocrine growth loop is provided by a correlation between EGF-R and TGF alpha, mRNA (P < .0001), and protein expression (P < .01). A trend toward inc reased expression of EGF-R and TGF alpha protein with dedifferentiatio n and a similar trend in the growth fraction suggest a role in tumor p rogression. Although there was a correlation between EGF-R and the pro liferative index (P < .01), no relationship was found between this lat ter parameter and TGF alpha immunoreactivity (P > .05), indicating tha t this growth factor may be linked with other aspects of malignant act ivity rather than directly stimulating proliferation. Copyright (C) 19 96 by W.B. Saunders Company.