Human Cancer Biology Serum Interleukin-6, Insulin, andHOMA-IR inMale Individuals with Colorectal Adenoma

Purpose: It is widely acknowledged that chronic low-grade inflammation plays a key role in the development of obesity-related insulin resistance and type 2 diabetes. The level of circulating interleukin-6 (IL-6), one of themajor proinflammatory adipokines, is correlatedwith obesity and insulin resistance, which are known to be risk factors for colorectal adenoma. We examined the association between the circulating level of IL-6 and the presence of colorectal adenoma. Experimental Design: In a total colonoscopy-based cross-sectional study conducted between January and December 2008, serum levels of IL-6 were measured in samples of venous blood obtained from 336 male participants attending health checkups (118 individuals with colorectal adenoma and 218 agematched controls) after an overnight fast. Results: In the colorectal adenoma group, the median levels of serum IL-6 (1.24 vs. 1.04 pg/mL; P1⁄4 0.01), triglyceride, insulin, and homeostasismodel assessment of insulin resistance (HOMA-IR)were to be significantly higher than those in the control group. When restricted to individuals with adenoma, levels of IL-6 were positively correlated with body mass index, insulin, and HOMA-IR. Multiple logistic analyses adjusted to include insulin orHOMA-IR showed that high levels of IL-6were associatedwith the presence of colorectal adenoma. There was no significant interaction of IL-6 with HOMA-IR to modify this association. Conclusions: Our findings suggest that increased serum levels of IL-6 are positively associated with the presence of colorectal adenoma in men, independently of insulin and HOMA-IR. Clin Cancer Res; 18(2);