IGFBP3 and colonic neoplasm: Several but not all prospective studies have found evidence for a positive association between higher levels of IGF-1 or the molar ratio of IGF-1 and its primary binding protein, IGF-binding protein 3 [11] (IGF-1/IGFBP-3 ratio) and colorectal and/or colon cancers [12]–[19].