IGF-I, IGFBP-3, and IGF-l/IGFBP-3 Ratio: No Association with Incident Colorectal Cancer in the Alpha-Tocopherol,Beta-Carotene Cancer Prevention Study

摘要

The insulin-like growth factor (IGF) signaling system is thought to affect tissue growth and development (1), with IGF-I and IGF binding protein-3 (IGFBP-3) having putative procarcinogenic and anticarcinogenic properties, respectively. A recent meta-analysis of four prospective studies found that IGF-I levels were positively associated with incident colorectal cancer (CRC), whereas IGFBP-3 and the IGF-I/IGFBP-3 molar ratio were less clearly associated (2). Two subsequent studies of the IGF proteins and CRC risk showed mixed results (3, 4). Herein, we describe a nested, case-cohort study of fasting serum IGF-I, IGFBP-3, and the IGF-I/IGFBP-3 molar ratio and CRC risk in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study.