Transforming growth factor-beta and prostate cancer

This review focuses on the possible role of transforming growth factor-beta isoforms 1-3 (TGF beta) in prostate cancer. TGF beta 1 appears to inhibit the cellular proliferation of normal prostate cells. Surprisingly, TGF beta 1 is overexpressed in prostate cancer. To help explain this apparent paradox, it has been revealed that with tumor progression, prostate cancer cells acquire reduced sensitivity to the growth-inhibitory effects of TGF beta 1. Aberrations of the TGF beta 1 signaling pathway at the prereceptor, receptor, or postreceptor level may lead to prostate cancer cell resistance to TGF beta 1 growth inhibition. Indirectly, elevated levels of TGF beta 1 may induce host effects that may be beneficial to prostate tumor growth by suppressing the immune system, promoting angiogenesis and extracellular matrix formation, and enhancing metastatic potential. Consequently, TGF beta 1 appears to be important in prostate carcinogenesis and tumorigenicity. TGF beta 2 and TGF beta 3 are only briefly presented as very little is known about their role in prostate cancer.