[Serum concentration of insulin, C-peptide and insulin-like growth factor I in patients with colon adenomas and colorectal cancer].

UNLABELLED: Colon carcinogenesis is a multi-steps process in which many growth factors are involved. In some studies the increased risk of colon cancer development was observed in patients with diabetes mellitus type 2 with accompanying hyperinsulinemia. It is also known that insulin-like growth factor I (IGF-I) plays an important role in proliferation, growth, differentiation and inhibiting apoptosis of both epithelial and carcinoma cells. The aim of the study was to evaluate the serum concentration of insulin, C-peptide and IGF-I in patients with colon adenomas and colorectal cancer.

MATERIALS AND METHODS: In 17 patients with colon cancer, 32 patients with colon adenomas and in 12 healthy persons the serum concentration of insulin, C-peptide and IGF-I was determined using ELISA kits.

RESULTS: In patients with colon cancer significantly higher serum IGF-I concentration comparing to the control group was observed (85.66 ng/ml vs. 60.96 ng/ml; p < 0.05). Higher IGF-I concentration was also observed in patients with distal tumors comparing to the proximal localisation (95.40 ng/ml vs. 64,65 ng/ml, p < 0.05) and in more differentiated tumors (84.36 ng/ml vs. 75.24 ng/ml). Similarly, higher C-peptide concentrations were observed in distal tumors (635.64 pmol/ I vs. 578.69 pmol/l) and in well-differentiated carcinoma (671.32 pmol/ I vs. 575.66 pmol/l). In patients with colon adenomatous polyps we also observed higher serum IGF-I concentrations I comparing to the control group (82.1 ng/ml vs. 60.96 ng/ml), in high dysplasia adenomas (84.12 ng/ml vs. 79.67 ng/ml) and in smaller adenomas to 1 cm diameter (97.98 ng/ml vs. 73.28 ng/ml), but the differences were not significant. We also observed higher concentration of C-peptide in patients with low grade dysplasia adenomas (665.24 pmol/l vs. 498.13 pmol/l) and with small polyps (611.51 pmol/l vs. 514.89 pmol/l). There were no differences in serum concentration of IGF-I and C-peptide between patients with tubular and villous adenomas. There was no statistical difference observed in insulin serum concentration in all groups of patients.

CONCLUSIONS: IGF-I is probably involved particularly in the early stage of colon carcinogenesis.