Serum interleukin 6 (IL-6) and C-reactive protein (CRP) levels in colorectal adenoma and cancer patients

Background: Colorectal cancer is one of the most common cancers of the gastrointestinal tract and the fourth cause of cancer death in the world. It has been shown that local chronic inflammation may lead to colorectal carcinogenesis via adenomatous polyps. Interleukin-6 and C-reactive protein are biomarkers of inflammation and indicators of the immune response to tumors. Methods: Serum levels of interleukin-6, carcinoembryonic antigen and carbohydrate antigen 19-9 were determined using immunoenzymatic assays, and C-reactive protein concentrations by immunoturbidimetric kits in 76 colorectal cancer patients before surgery, in 38 colorectal adenoma patients and in 35 healthy controls. Results: Serum levels of interleukin-6, C-reactive protein and carcinoembryonic antigen were significantly higher in cancer patients when compared to adenoma patients and healthy subjects, and increased in more advanced stages of disease and in patients with non-resectable tumors. Based on Cox's analysis, the elevated preoperative serum level of C-reactive protein was an independent significant prognostic factor for patients' survival. Conclusions: Our findings suggest the usefulness of interleukin-6 in the diagnosis of colorectal cancer patients and C-reactive protein in the survival prognosis.