Salivary metabolite signatures of oral cancer and leukoplakia through gas chromatography-mass spectrometry

Saliva contains a large array of metabolites, many of which can be informative for the detection of diseases. Gas chromatography-mass spectrometry (GC-MS) is a system that has long been used for metabolite profiling owing to its sensitivity, specificity, reproducibility and synchronized analysis; it has relatively broad coverage of compound classes including sugars, sugar alcohols, glycosides and lipophilic compounds.The present study was conducted to explore the use of GC-MS in assessing variation in salivary metabolites and to recognize the metabolites which can be used as disease diagnostic tools and metabolite markers for detection of oral squamous cell carcinoma.The present study included clinically and histopathologically confirmed oral squamous cell carcinoma (OSCC) and oral leukoplakia patients (OLK) and the control group. Patients were divided into three groups: OSCC (n = 30), OLK (n = 30) and healthy individuals as controls (n = 30). Patients were refrained from eating, drinking, smoking or oral hygiene procedures for at least 1.5 h before the collection. Saliva was collected between 9.00 and 10.00 am. Samples were stored at -80°C. Filtered samples were used for GC-MS.Fifteen compounds differed significantly between control, OLK and OSCC. These metabolites were decanedioic acid, 2-methyloctacosane, eicosane, octane, 3,5-dimethyl, pentadecane, hentriacontane, 5, 5-diethylpentadecane, nonadecane, oxalic acid, 6-phenylundecanea, l-proline, 2-furancarboxamide, 2-isopropyl-5-methyl-1-heptanol, pentanoic acid, Docosane.The findings of the study suggest the application of salivary metabolomics as a promising tool in the identification of tumor-specific biomarkers in early diagnosis and prediction of OSCC and oral leukoplakia. In future, standardizing the protocol for salivary analysis and overcoming some of the limitations will be helpful to establish salivary metabolomics as a reliable, the highly sensitive and specific method for clinical use as an independent diagnostic aid.