Oxidative stress and tumor progression in colorectal cancer

Abstract

Background/aims: Elevated oxidative status has been found in many types of cancer cells. Recent studies have shown that the enzymatic product of thymidine phosphorylase (TP) generated reactive oxygen species (ROS) within cancer cells. The aim of this study was thus to evaluate the signal transduction pathway and the role of ROS in colorectal cancer.

Methodology: Blood specimens were obtained from the drainage vein of the tumor during operation in 76 patients with colorectal cancer. Serum ROS levels were measured using the derivative-Reactive Oxygen Metabolites (d-ROM) test and serum TP levels were examined by a highly sensitive ELISA method.

Results: There was no significant correlation between serum levels of ROS and TP. Serum ROS levels were elevated in proportion to tumor invasion and had a significant positive correlation with tumor size (p < 0.05). However, they did not increase in patients with liver metastasis.

Conclusions: These findings suggest that ROS are independent of TP-triggered signaling transduction and are associated with increased tumor invasion, but not liver metastasis in patients with colorectal cancer. From this point of view, new strategies related to ROS may provide improved therapeutic results as well as a preventative effect on carcinogenesis of the colorectum.