IGF1 and cancer: Furthermore, IGFBP-3 levels have been inversely associated with prostate carcinogenesis and the negative correlation between IGFBP-3 levels and cancer risk is consistent with a protective role of IGFBP-3, i.e., high IGFBP-3 concentrations may lead to reduced IGF-I bioavailability (Koutsilieris et al., 1995; Bogdanos et al., 2003; Papatsoris et al., 2005; Werner and Bruchim, 2009).