Immunoexpression of tumour necrosis factor-alpha and its receptors 1 and 2correlates with proliferation/apoptosis equilibrium in normal, hyperplasicand carcinomatous human prostate

Immunohistochemical and semiquantitative study of TNF-alpha, its receptors types 1 (TNFR1) and 2 (TNFR2), cell proliferation (Ki-67 nuclear antigen), and apoptosis (Tunel method) was carried out in human prostates, in normal healthy conditions, as well as in benign prostatic hyperplasia (BPH) and pr ostatic carcinoma (PC), Cell proliferation was higher in BPH than in normal prostates, and even higher in PC, mainly in neoformations showing a microg landular pattern. The apoptotic index was similar in BPH and normal prostat es, and increased significantly in PC with independence of the pattern. In BPH, immunoreaction to TNF-alpha decreased as compared with that of normal prostates, while immunoreactions to both TNF-alpha receptors increased. Thi s suggests a feedback downregulation of the factor, and that the low TNF-al pha activity in BPH are compensated by the increased amount of receptors. I n PC, immunoreaction to TNF-alpha and its two receptors increased markedly, suggesting that the TNF-induced effects are also increased, Contrarily to cell proliferation immunoexpression, PC reaction to TNFR2 was stronger in t he papillar pattern than in the micrograndular pattern, and this suggests a n inverse correlation between TNFR2 expression and cell proliferation. (C) 2000 Academic Press.