Metabolomic signature of esophageal cancer.
21 Background: Esophageal cancer is a pervasive malignancy, and early detection combined with newer therapeutic targets could alter the landscape of this condition. Metabolomic profiling offers one such innovative opportunity. We applied metabolomic techniques to identify urinary metabolites uniquely associated with this condition. Methods: Urine samples from patients with histologically confirmed esophageal cancer (n=66) and healthy volunteers (n=25) were collected and examined using 1H-NMR spectroscopy. Targeted profiling of spectra using Chenomx NMR Suite 7.0 software permitted detection and quantification of 66 distinct metabolites. Unsupervised (principal component analysis, PCA) and supervised (partial least-squares discriminant analysis, PLS-DA) multivariate pattern recognition techniques were applied to discriminate between sample spectra of esophageal cancer patients and healthy volunteers using SIMCA-P (version 11, Umetrics, Umeå, Sweden). Results: Significant differences were found when comparing concentrations of 59 metabolites in urines of healthy volunteers and esophageal cancer patients. Those metabolites contributing most class discriminating information included choline, urea, 2-aminobutyrate, and 3-hydoxybutyrate. Clear distinctions between patients with esophageal cancer and healthy controls were noted when PLS-DA was applied to the data set. Model parameters for both goodness of fit R2, and predictive capability Q2, were high (R2 = 0.867; Q2 = 0.732). Model validity was tested using response permutation and results were suggestive of excellent predictive power (see Figure). Conclusions: Urinary metabolomics identified a discrete signature associated with esophageal cancer compared to healthy controls. This profile has the potential to aid in diagnosis and development of new therapeutic targets.