Association of Insulin-Related Serum Factors with Colorectal Polyp Number and Type in Adult Males

Background: Dysregulated insulin signaling is thought to contribute to cancer risk. Methods: To determine if insulin-related serum factors are associated with colon polyps, 126 asymptomatic men (48-65 years) were recruited at colonoscopy. Blood was collected. Odds ratios were determined using polytomous logistic regression for polyp number and type. Results: Males with serum C-peptide concentration >3.3 ng/mL were 3.8 times more likely to have an adenoma relative to no polyp than those with C-peptide <= 1.8 ng/mL. As C-peptide tertile increased, an individual was 2 times more likely to have an adenoma (P = 0.01) than no polyp. There were no associations between insulin-like growth factor or its binding proteins with polyp number or type. Males with soluble receptor for advanced glycation end products (sRAGE) concentration >120.4 pg/mL were 0.25 times less likely to have >= 3 polyps relative to no polyps compared with males with sRAGE <= 94.5 pg/mL. For each increase in sRAGE tertile, a man was 0.5 times less likely to have >= 3 polyps than no polyps (P = 0.03). Compared with males with a serum vascular endothelial growth factor (VEGF) concentration <= 104.7 pg/mL, males with a serum VEGF concentration >184.2 pg/mL were 3.4 times more likely to have >= 3 polyps relative to no polyps. As the VEGF tertile increased, a man was 1.9 times more likely to have >= 3 polyps than no polyps (P = 0.049). Conclusions: Serum concentrations of C-peptide, sRAGE, and VEGF may indicate which men could benefit most from colonoscopy. Impact: Identification of biomarkers could reduce medical costs through the elimination of colonoscopies on low-risk individuals. (C) 2014 AACR.