Estimation of salivary lactate dehydrogenase in oral squamous cell carcinoma, oral leukoplakia, and smokers

Introduction: Lactate dehydrogenase (LDH) is an enzyme seen within every cell during their normal metabolic function. It is always confined within the cell cytoplasm and it becomes extracellular only when a cell dies. The extracellular presence of LDH is related to cell necrosis and tissue breakdown. Therefore, we designed a study to estimate and compare LDH levels in the saliva of patients with oral cancer, oral leukoplakia (OL), and smokers without lesions and in controls. Materials and Methods: A total of 81 subjects of both genders, between the ages of 20 and 70 years, were included in the study. The study group was divided into four: group I-controls ( n = 20), Group II-smokers ( n = 20), Group III-subjects with OL ( n = 20), and Group IV-subjects with oral squamous cell carcinoma (OSCC) ( n = 21). Five milliliters of unstimulated salivary sample was collected from each participant, and salivary LDH level was measured. The obtained values were tabulated and statistically analyzed. P < 0.05 was considered to be statistically significant. Results: The difference in LDH levels among the four groups was found to "BE" statistically significant. LDH values showed a marked increase in the leukoplakia group (49.79 +/- 19.88 IU/L) and OSCC group (106.97 +/- 32.75 IU/L) when compared to controls and smokers. Conclusion: We found that salivary LDH was increased in patients with leukoplakia and OSCC. Smoking alone did not produce any alterations in salivary LDH. It is possible that salivary LDH could be a potential biomarker to identify early premalignant or malignant changes in smokers.