Analysis of urinary nucleosides as potential tumor markers in human colorectal cancer by high performance liquid chromatography/electrospray ionization tandem mass spectrometry

Background: Increased levels of modified nucleosides have been observed in urine from patients suffering from several cancers. In this study, we evaluated whether urinary nucleosides can serve as potential tumor markers for colorectal cancer by high performance liquid chromatography-electrospray/tandem mass spectrometry (HPLC/ESI-MS/MS). Methods: A simple and specific method based on HPLC/ESI-MS/MS was developed to determine the urinary nucleosides from patients with colorectal cancer. We studied the excretion patterns of nucleosides in urine from 26 patients with colorectal cancer and 18 healthy controls. Results: The LC/MS/MS approach with selective reaction monitoring (SRM) allowed for the sensitive determination of nucleosides in human urine samples with colorectal cancer. The mean levels of 5 urinary nucleosides (adenosine, cytidine, N-2,N-2-dimethylguanine, 8-hydroxy-2'-deoxyguanosine and uridine) were significantly higher in the patients with colorectal cancer than in the healthy adults. Conclusions: The results indicate that urinary nucleosides determined by LC/MS/MS may be useful as biological markers for colorectal cancer. Our findings suggest that LC/MS/MS is a highly specific and sensitive method for rapidly screening a large number of nucleoside that may be useful as markers for cancer in humans. (C) 2008 Elsevier B.V. All rights reserved.