Plasma metabolomic profiling distinguishes right-sided from left-sided colon cancer

Background Many studies have demonstrated that right-sided colon cancer (RCC) has a higher mortality rate and worse prognosis than left-sided colon cancer (LCC). However, the underlying biological mechanism that can account for these differences is unclear. Methods: In this study, plasma metabolic profiles in 147 LCC patients and 105 RCC patients were systematically analyzed by the ultra high performance liquid chromatography quadruple time-of-flight mass spectrometry (UHPLC-QTOF/MS) platform in conjunction with univariate and multivariate statistical analysis. Results: Metabolic signatures revealed considerable differences between patients with RCC and LCC, and clear separations were observed between the two groups in partial least-squares discriminant analysis score plots. In total, six metabolites were identified as potential metabolite markers for tumor location in RCC compared with LCC, including upregulated trimethylamine N-oxide and indoxyl sulfate, and downregulated anserine, L-targinine, gamma-glutamyl-gamma-aminobutyraldehyde and pyridoxal 5'-phosphate. These differences highlight that significant alternations occur in the pathways of methane metabolism, arginine and proline metabolism, histidine metabolism, beta-alanine metabolism and vitamin B6 metabolism in RCC compared with LCC. Conclusions: Identified biomarkers and metabolic pathways may facilate our understanding of the different mortality rates and prognoses between RCC and LCC.