Evaluation of salivary gamma-glutamyl transpeptidase as a biomarker in oral squamous cell carcinoma and precancerous lesions

BACKGROUND: Oral cancer is such a common malignancy, but its manifestations are usually asymptomatic, and by the time the lesion is diagnosed its invasion is deep. This makes the survival rate poor and also the treatment rendered during such stages is extensive and debilitating. In this regard, a novel approach has been advocated in the estimation of biomarkers in the body fluids. Gamma-glutamyl transpeptidase (GGT)/gamma-glutamyl transferase is an enzyme that is essential for the absorption of amino acids, especially in the degradation of glutathione. Its activity is increased in oral cancer and precancerous lesions. AIMS AND OBJECTIVES: The purpose of this study was to assess the activity and concentration of GGT in precancerous and cancerous patients in comparison with normal patients and also to assess its efficacy as an effective tumor marker. MATERIALS AND METHODS: The study population comprised a total of 75 patients who were categorized into three groups as normal patients (25 cases in Group A), patients with precancerous lesions (25 patients in Group B) and patients with oral squamous cell carcinoma (25 cases in Group C). 5 ml of whole unstimulated saliva collection was done, it was centrifuged at 3000 rpm for 15 min and the supernatant thus obtained was used for the estimation of GGT levels. The detection was done by photometric method reading the absorbance at 405 nm. RESULTS: Group A patients had values of GGT ranging from 4 to 30U/L with a mean of 16.7 ± 1.94U/L. Group B had activity of GGT ranging from 39 to 65 U/L with a mean of 50.4 ± 1.67U/L. In group C, the evaluated GGT activity was between 53 and 86 U/L and the mean was 70 ± 2.37 U/L. Statistical analysis using Chi-square test was conducted. Correlations between Group A and Group B and between Groups A and C showed a statistically significant relation (P < 0.005). CONCLUSION: Salivary gamma-glutamyl transferase activity can be used effectively as a tumor marker, and further studies with a larger sample size can be done to correlate this finding.