Clinical significance of serum cytokine measurements in untreated colorectal cancer patients: soluble tumor necrosis factor receptor type I--an independent prognostic factor.

The aim of this study was to exploit the potential clinical use of circulating cytokine measurements in colorectal cancer (CRC) patients. The levels of cytokines and cytokine receptors were assessed by ELISA in the sera of 50 healthy volunteers and 157 patients with previously untreated CRC and then related to clinicopathological features and prognosis. All tumors were verified histologically as colorectal adenocarcinomas and staged according to TNM classification. The levels of circulating interleukin (IL)-6, IL-8, macrophage colony-stimulating factor (M-CSF) and interleukin 1 receptor antagonist (IL-1ra) significantly increased with the clinical stage of CRC, and the levels of IL-6, soluble tumor necrosis factor (sTNF) receptor type I (RI), soluble interleukin 2 receptor alpha and TNFalpha with tumor grade, while IL-6, IL-8, M-CSF, IL-1ra and sTNF RI levels significantly rose with bowel wall invasion. None of the cytokine or soluble cytokine receptor levels were influenced by age, gender and colon versus rectum localization. sTNF RI, IL-8, IL-6 and vascular endothelial growth factor measurements demonstrated the highest diagnostic sensitivity. sTNF RI was found elevated in the greatest percentage of all CRC patients, in the greatest proportion of stage I patients and presented the best diagnostic sensitivity. In addition, the sTNF RI level strongly correlated with tumor grade and invasion and proved to be an independent prognostic factor.