Suramin and serum insulin-like growth factor levels in metastatic cancer patients

Suramin, a polysulphonated naphthylurea, inhibits the activity of several growth factors in in vitro experiments and clinical responses have been reported in human solid tumors. We decided to investigate the relationship between suramin treatment and serum levels of insulin-like growth factor I (IGF-I) and II (IGF-II) in advanced breast, prostate and lung cancer patients. The serum IGF-I, IGF-II levels were determined by radioimmunoassay. A significant decline of IGF-I and IGF-II serum levels was demonstrated in suramin treated patients. Our results suggest that suramin-induced IGF suppression could be one of the possible mechanisms of suramin action.