Immunohistochemical comparative analysis of transforming growth factor alpha, epidermal growth factor, and epidermal growth factor receptor in normal, hyperplastic and neoplastic human prostates

Immunoreaction to TGF-alpha was limited to the basal epithelial cells of fo cal areas in the normal prostates. In benign prostatic hyperplasia (BPH) th e immunostained areas were more widespread and immunolabelling was observed in both basal and columnar (secretory) cells of the epithelium. Some cells in the connective tissue stroma were also stained. In prostatic adenocarci noma, epithelial immunostaining was even more extensive and intense than in BPH, and some stromal cells were also stained. Epidermal growth factor (EG F) immunostaining was only present in some basal cells in normal prostates. In BPH, this immunoreaction was strong in the basal cells and even stronge r in the secretory cells, In prostatic cancer, the intensity of epithelial cell immunoreactivity was intermediate between that of normal prostates and that of BPH specimens. EGF-receptor immunostaining was focal and located i n the basal cells in normal prostates. In BPH, labelling was also localized in basal cells but extended to wider areas, Some stromal cells appeared we akly labelled. In the prostatic carcinoma, both basal and columnar cells ap peared stained and the number of immunolabelled stromal cells was higher th an in BPH. The results presented suggest that, in normal conditions, EGF an d TGF-alpha act as autocrine growth factors for the basal cells of the pros tatic epithelium. In BPH this action is maintained and, in addition, the co lumnar cells start to secrete both factors which are bound by the basal cel l receptors, giving rise to a paracrine regulation which probably overstimu lates basal cell proliferation, In prostatic carcinoma, besides these regul atory mechanisms, the acquisition of EGF-receptors by the secretory cells d evelops an autocrine regulation which might induce their proliferation. (C) 1999 Academic Press.