Salivary enzymes and oxidant-antioxidant parameters as biomarkers of head and neck cancer: Correlation between blood and saliva

Background: Studies with saliva are of immense advantage as the process of it collection from humans is a noninvasive method and can be repeated with least compliance problems. In this study, the levels of lactate dehydrogenase (LDH), amylase, reduced glutathione (GSH), glutathione S-transferase (GST), protein-bound sialic acid (PBSA), lipid peroxidation (LPO) and total antioxidant capacity (TAC) were analysed in the blood and saliva samples of head and neck cancer (HNC) patients and compared it with age-matched healthy controls (N = 30) to explore the usefulness of the parameters as an endpoint biomarkers. Materials and Methods: HNC patients visiting hospital for treatment (n = 31) were the participants of the study; age- and sex-matched healthy controls were included. Levels of LDH, amylase, PBSA, LPO (as malondialdehyde), GSH, GST and TAC were analysed in whole, unstimulated saliva samples. Results: The levels of LDH, amylase, PBSA and LPO were significantly higher, and levels of GSH, GST and TAC were significantly lower in blood and saliva of HNC patients when compared to healthy controls (P < 0.001). There was statistically significant correlation between blood and saliva with regard to the levels of amylase and GSH (P < 0.001). Conclusions: This study demonstrated significant changes in the biochemical parameters of blood and saliva in HNC patients and correlation of salivary GSH and amylase with corresponding levels of blood. Salivary biochemical parameters could serve as sensitive and convenient biomarkers of HNC.