Studies on the proliferation, secretory activities, and epidermal growth factor receptor expression in benign prostatic hyperplasia explant cultures.

Short term explant cultures of benign prostatic hyperplasia (BPH) tissues were studied immunohistochemically to characterise both the morphological changes within the explant tissue and the cellular origin of the epithelial cell outgrowth. Altered patterns of expression of cytokeratins, prostate specific antigen (PSA) prostatic acid phosphatase (PAP), and epidermal growth factor (EGF) receptor were observed. After sloughing of the secretory epithelium in the majority of the acini repopulation and outgrowth of a monolayer was accomplished by cells which were strongly positive for stratifying keratin and EGF receptor and negative for PAP and PSA, indicative of a basal cell phenotype. The peak of proliferation in the acini, as assessed by Ki-67 immunohistochemistry, occurred after 2-4 days in culture. Preliminary studies on BPH tissue xenografts in nude mice indicated that better preservation of normal morphology, secretory activity, and antigen expression could be achieved.