BACKGROUND: Diabetes mellitus a common metabolic disorder with hyperglycemia, is caused by the interaction of genetic and environmental factors. Approximately 12~20% of diabetic patients have risk of colorectal cancer. Recent studies revealed that the insulin-like growth factor system (IGFs) plays an important role in tumor occurrence. This study thus investigated the relationship between IGFs-related proteins in diabetic patients and the incidence of colorectal carcinoma.

MATERIAL AND METHODS: A retrospective study was performed in a total of 206 individuals, including 85 diagnosed with diabetes. The incidence of colorectal cancer was tracked, along with the detection of IGFs expression in serum. During the surgical resection, tumor tissues and adjacent tissues were collected and quantified for IGFs expression level.

RESULTS: We found no significant difference in age or sex between the diabetic and control groups. Diabetic patients, however, had elevated body weight and higher incidence of colorectal cancer compared to non-diabetic controls (p<0.05). The diabetic group also had higher IGF-I and IGF-IR mRNA levels in serum, while IGFBP-6 expression was down-regulated. In comparison to adjacent healthy tissues, tumor tissue had higher levels of IGF-I and IGF-IR but lower levels of IGFBP-6 (p<0.05).

CONCLUSIONS: Our study showed higher incidence of colorectal cancer in diabetics compared to non-diabetics. The occurrence of colorectal cancer in diabetic patients may be associated with elevated IGFs-related protein expression level.

Keywords: Case-Control Studies, Colorectal Neoplasms - epidemiology, Diabetes Mellitus - blood, Incidence, Insulin-Like Growth Factor Binding Protein 2 - blood, Insulin-Like Growth Factor Binding Protein 6 - blood, Insulin-Like Growth Factor I - metabolism, Insulin-Like Growth Factor II - metabolism, Receptor, IGF Type 1 - blood