IGF-1 and IGFBP-3 in cancer patients

Abstract

Growth factors called somatomedins have been isolated from human plasma and described in the seventies of the last centry. Insulin-like growth factors and their binding proteins are synthesized mainly in the liver, this process is regulated by the growth hormone. Insulin-like effects of IGF-1 are primarily stimulating the uptake of glucose by adipocytes and muscle cells. Moreover, IGF-1 stimulates cell division, plays a significant role in the processes of differentiation, maturation, repair of damaged DNA and apoptosis. Insulin-like growth factor binding proteins by binding IGF-1 modulate its biological activity, counteract the potentially carcinogenic activity of unbound IGF-1. Furthermore, IGFBPs, especially IGFBP-3, have independent effects on cell growth, for example, IGFPB-3 has proapoptotic activities. Elevated level of IGF-1 with simultaneously reduced concentration of its binding protein are considered risk factors for the development of a number of diseases, including neoplastic diseases. High serum concentrations of IGF-1 and low levels of IGFBP-3 are associated with increased risks of lung, breast, prostate, and colorectal cancers.