Heparin-binding fibroblast growth factors and prostate cancer

Studies of model rat prostate tissue and derived cells indicate the insulin-like (IGF), epidermal growth factor (EGF), transforming growth factor beta (TGF-beta) and heparin-binding fibroblast growth factor (HBGF) families and their receptors may play important roles in regulation of normal prostate cell growth. Tumor cells at different levels in the progression from slow-growing, hormone-dependence to fast-growing, hormone-independence exhibit distinct alterations in expression of specific growth factors and their receptor phenotype. Distinct IGF-I and HBGF mRNAs are constitutively expressed in the mesenchymal cells of slow-tumors, but alteration in HBGF receptor phenotype occurs in the epithelial cells. Fast-tumors exhibit even higher constitutive expression of multiple HBGFs. Splice variants in cDNA for the HBGF receptor in fast-tumors suggest constitutive expression of an intracellular receptor, that together with intracellular HBGFs, may constitute an intracellular autocrine system that is independent of exogenous hormones and growth factors.