Elevated urinary 8-oxo-7,8-dihydro-2′-deoxyguanosine and serum uric acid are associated with progression and are prognostic factors of colorectal cancer

BACKGROUND AND PURPOSE: Oxidative stress is closely related to the pathogenesis of colorectal cancer (CRC). 8-Oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodG) is a typical bio-marker of oxidative stress. Serum uric acid (SUA) is one of the most abundant molecules with antioxidant properties in human blood. This study aimed to explore whether 8-oxodG and SUA could be prognostic factors of CRC. METHODS: Urinary 8-oxodG level was analyzed using ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). SUA concentration was measured using an automatic biochemistry analyzer. Seventy-three newly diagnosed Chinese CRC patients were included. According to the mean level of urinary 8-oxodG or SUA, patients were divided into high and low groups. RESULTS: The level of 8-oxodG and SUA gradually elevated from stage I to stage IV in CRC patients. High 8-oxodG concentration and SUA levels were associated with worse overall survival (P=0.03). In the stage II and stage III CRC group, no statistically significant relationship was found between the urinary 8-oxodG level and overall survival or between the SUA level and overall survival. Nevertheless, when these two biomarkers were combined, there was a statistically significant association with overall survival (P=0.02). CONCLUSION: Elevated urinary 8-oxodG and SUA levels measured at the time of diagnosis were associated with the progression of CRC. Both urinary 8-oxodG and SUA might be valuable as CRC prognostic factors, and the combination of the two biomarkers might help to determine the prognoses of CRC, particularly in stage II and stage III CRC patients.