Higher Expression of Proteins in IGF/IR Axes in Colorectal Cancer is Associated with Type 2 Diabetes Mellitus

Preexisting type 2 diabetes mellitus (preDM) increases occurrence and mortality of colorectal cancer (CRC). Insulin growth factor (IGF)/insulin receptor (IR) axes play an important role in the development of both diabetes and CRC. We aimed to explore the characteristics of proteins expression in IGF/IR axes in CRC tissues with preDM. Two hundred fifty CRC patients in West China hospital were included in analysis. Among them, 125 patients had history of diabetes matched by 125 CRC without diabetes at a 1:1 ratio. Immunohistochemical staining was used to detect the expression of proteins in IGF/IR axis. More positive expression of IGF-1, IGF-1R and IR were found in CRC group with diabetes than in non-diabetes group. No difference was detected in the expression of IR substrate-1, IR substrate-2, IGF-2, IGF binding protein 3, and mammalian target of rapamycin between two groups. Multivariate analysis showed that diabetes history was associated with all of the expression of IGF-1, IGF-1R and IR, and higher T staging and lymph node metastasis were respectively independent factors of IGF-1 and IGF-1R expression in CRC patients. Besides, IGF-1 expression was positively associated with IGF-1R and IR expression in all CRC tissues, and the association of IGF-1 and IR expression seemed to be closer in diabetes group than in non-diabetes group. Higher expression of IGF-1, IGF-1R and IR proteins in CRC was associated with diabetes, suggesting IGF-1/IR signaling may play a special part in development of CRC in patients with diabetes.