Histopathological differentiation of oral squamous cell carcinoma and salivary lactate dehydrogenase: A biochemical study

CONTEXT: Early diagnosis of oral cancer is a priority health objective, in which oral health professionals may play a pivotal role. Detection should lead to less damage from cancer therapy and to a better prognosis. AIMS: The aim was to estimate and compare the salivary lactate dehydrogenase (LDH) levels in various histological differentiation of oral squamous cell carcinoma (OSCC) patients and normal subjects. SETTINGS AND DESIGN: Hospital-based setting, case-control study. SUBJECTS AND METHODS: A case–control study was undertaken comprising 30 OSCC patients and 30 healthy controls. The OSCC patients were grouped into well-differentiated, moderately differentiated and poorly differentiated OSCC based on their histological tumor differentiation. Unstimulated whole saliva was collected, assayed for LDH levels using a standard kit and measured spectrophotometrically at 340 nm. STATISTICAL ANALYSIS USED: The results obtained were subjected to statistical analysis using Kruskal–Wallis and Mann–Whitney U-tests. Spearman's correlation was used to correlate the histological tumor differentiation with the salivary LDH levels. RESULTS: The mean salivary LDH levels in the control group, well-differentiated OSCC group, moderately differentiated OSCC group, and poorly differentiated OSCC group were 117.33 ± 19.37 IU/L, 355.83 ± 16.73 IU/L, 484.18 ± 25.84 IU/L, and 620.35 ± 18.69 IU/L, respectively. The difference in the mean salivary LDH levels was statistically significant among the various groups (Kruskal–Wallis χ(2) = 50.820, P < 0.001). Spearman's correlation showed significant difference between salivary LDH levels and histological differentiation of OSCC (r = −0.689, P < 0.01). CONCLUSIONS: The salivary LDH levels were higher in OSCC patients when compared to the healthy controls. The salivary LDH levels were found to be the highest among the poorly differentiated OSCC.