Metabolomics: A new paradigm for cancer biomarker discovery

Currently, individual molecular biomarkersare often used to detect cancers. However, to identify cancer-specific signatures appropriate for clinical use, a paradigm shift is necessary in terms of using multiple molecular profiling techniques to identify new prognostic biomarkers and therapeutic targets, and to understand the aberrant biochemical pathways. Metabolomics, a new omics, provides a holistic view of the cellular dynamic behavior derived from various endogenetic and exogenetic perturbations as well as genomics, transcriptomics and proteomics. To simultaneously assess a broad range of metabolites, we have developed profiling techniques based on capillary electrophoresis-mass spectrometry (CE-MS) that can quantify charged molecules,principally those involved in the central metabolic pathways; i.e., glycolysis, pentose phosphate pathway, amino acid pathway, nucleotide pathway, tricarboxylic cycle, and urea cycle. Because tumors exhibit unique cellular metabolic profiles to survive or to enable excessive proliferation in an aberrant microenvironment, CE-MS can offera significant opportunity to fully understand cancer metabolism. Here, we provide an overview of CE-MS-based metabolomics and two applications; 1) pathway-level metabolic variation to provide novel insights into the microenvironmentof human tumor tissues, and 2) the potential use of salivary metabolites in cancer detection.