Salivary metabolomics for oral cancer detection

Saliva is an informative biofluid that can be used to monitor a wide range of oral and systemic diseases. This medium has gained much attention as a diagnostic fluid because of its simple collection, non-invasiveness, and low cost. Many studies have been conducted to identify diagnostic markers in saliva for several diseases, including HIV, diabetes, viral hepatitis and, importantly, cancers. The recently developed comprehensive molecular profiling approaches, such as transcriptomics and proteomics, can accelerate these studies. Metabolomics, profiling of all intracellular metabolites, has become a powerful new omics tool that can provide insight into cellular functions and facilitate biomarker discovery. Although there are several approaches to profiling metabolites, capillary electrophoresis time-of-flight-mass spectrometry (CE-TOFMS) has a prominent advantage because it enables comprehensive, simultaneous and quantitative analysis of key metabolites in various pathways, such as glycolysis, pentose phosphate pathway, tricarboxylic acid cycle and urea cycle, as well as amino acid and nucleotide metabolism. Thus, this method is well-suited to biomarker discovery in cancer cells because there are diverse metabolic aberrations related to energy metabolism and cellular proliferation in cancer cells. We recently applied CE-TOFMS-based metabolomic analysis to evaluate the potential of using the salivary metabolomic signature to detect oral cancer (oral squamous cell carcinoma cancers). The metabolic fingerprints embedded in the salivary specimens showed a prominent difference between oral cancer and healthy controls. Here, we introduce the marriage of CE and TOFMS, which has the potential to provide a state-of-the art salivary-based detection method for oral cancer.