IGF-I and IGF-II in relation to colorectal cancer.

Recent data suggest that the IGF system plays an important role in the pathogenesis of several forms of human cancer, and there is evidence that IGFs acting in an autocrine and paracrine manner may also affect colorectal cancer risk. We have conducted a case-control study on the island of Crete, Greece, to examine the potential relation between circulating IGF-I and -II and their major binding protein (IGF-BP3), on the one hand, and colorectal cancer, on the other. IGF-I, IGF-II and IGF-BP3 were determined in the serum from 41 patients with colorectal cancer and 50 healthy controls; data were analyzed using unconditional multiple logistic regression, adjusting for age, gender, education, height and BMI, as well as mutually. Both IGF-I and IGF-II were positively, while IGF-BP3 was inversely, associated with risk for colorectal cancer, though none of these relations reached statistical significance. However, individuals with IGF-I and -II values in the upper 2 tertiles of the respective distributions had a significantly elevated odds ratio for colorectal cancer (OR = 5.2, 95% confidence interval 1.0-26.8) compared with those in the lower tertile in both distributions. Our results provide evidence that high levels of circulating IGF-I and -II might be associated with colorectal cancer.