Abstract 4637: Intra-individual changes in circulating IGF-1 and IGF-1/IGFBP-3 molar ratio are associated with colorectal adenomatous polyps presence

Background: High levels of circulating insulin-like growth factor-1 (IGF-1) have been associated with increased risks of several cancers, including colorectal cancer. Methods: In a sub-cohort of the Insulin Resistance and Atherosclerosis Study (IRAS), we examined the associations between circulating IGF-1 and IGF-1/IGFBP-3 molar ratios, as well as their change patterns during 10-year follow-up, with the presence of colorectal adenomatous polyps at the end of the follow-up. Results: The general trend was decrease of both variables with age. Based on this trend, two patterns were considered: “no increase” (variation within 15% of baseline and/or decrease) and “ever increase” (at least one increase of > 15%). In the subgroup of participants with normal glucose tolerance, “ever increase” was positively associated with colorectal adenoma: ORs were 3.65 (1.30-10.8) and 2.83 (1.00-8.22) for IGF-1 and IGF-1/IGFBP-3, respectively. No association was found between actual levels of IGF-1 or IGF-1/IGFBP-3 at any time point and the presence of colorectal adenoma. Conclusion: Our data suggest that increase in circulating IGF-1 and IGF-1/IGFBP-3 may represent an unnatural trend of a disturbed signaling pathway, which could favor the development of precancerous lesions, such as colorectal adenoma. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4637. doi:10.1158/1538-7445.AM2011-4637