Salivary 8-hydroxy-2-deoxyguanosine, malondialdehyde, vitamin C, and vitamin E in oral pre-cancer and cancer: diagnostic value and free radical mechanism of action

Objectives The objectives of this study are to analyze oxidative DNA and lipid damage using salivary 8-hydroxy-2-deoxyguanosine (8-OHdG), malondialdehyde (MDA), and vitamins C and E in oral lichen planus lesions, oral leukoplakia, oral submucous fibrosis, oral squamous cell carcinoma (SCC), and controls and to determine the value of salivary biomarkers in the diagnosis of oral pre-cancer and cancer patients. Materials and methods Unstimulated saliva was collected from a group of patients diagnosed with 40 oral squamous cell carcinoma (OSCC), 40 oral lichen planus lesions, 40 oral leukoplakia, 40 oral submucous fibrosis, and from a control group of healthy age-and gender-matched individuals. Salivary 8-OHdG, MDA, and vitamins C and E were measured. Results Squamous cell carcinoma and pre-cancer patients showed significantly higher levels of salivary 8-OHdG and MDA and lower levels of vitamins C and E when compared to levels in healthy normal subjects. The specificity and sensitivity of the combination of 8-OHdG, MDA, vitamin C, and vitamin E are high for the diagnosis of oral pre-cancer and SCC compared to an individual biomarker approach using either 8-OHdG, MDA, or vitamin C and vitamin E independently. Conclusions This study indicates the presence of oxidative DNA and lipid damage in pre-cancerous and SCC patients. It is postulated that the mechanism may have a significant link to carcinogenesis in oral cancer. Detection of salivary 8OHdG, MDA, vitamin C, and vitamin E can act as suitable diagnostic biomarkers of oral pre-cancer and cancer. Clinical relevance Of clinical importance is that salivary 8OHdG, MDA, vitamin C, and vitamin E could play a significant role in oral cancer and pre-cancer patients and could therefore be useful for diagnosis in patients with oral lichen planus lesions, oral leukoplakia, oral submucous fibrosis, and oral squamous cell carcinoma.