Evaluation of Genetic Polymorphisms in Glutathione S-Transferase Theta1, Glutathione S-Transferase Mu1, and Glutathione S-Transferase Mu3 in Oral Leukoplakia and Oral Squamous Cell Carcinoma with Deleterious Habits using Polymerase Chain Reaction.

BACKGROUND

Oral squamous cell carcinoma (OSCC) is the sixth most common cancer in the world. As per previous studies, most patients who develop oral cancer are elderly males who are heavy users of tobacco and alcohol; however, the incidence is increasing in younger individuals and in those who neither smoke nor drink. Many of the genes that code for the detoxification enzymes are polymorphic with abnormal activity profiles.

OBJECTIVE

The aim of this study was to evaluate the risk of development of oral leukoplakia (OLP) and OSCC in glutathione S-transferase polymorphisms genes in the east coast of Andhra Pradesh population with tobacco consumption habit and habit-free controls using polymerase chain reaction (PCR-restriction fragment length polymorphism).

METHODS

This study included 15 patients each with histologically proven epithelial dysplasia and OSCC and compared with age- and gender-related controls with no tobacco habits in any form. A volume of 2 ml of blood sample was collected into presterilized vials containing ethylenediaminetetracetic acid from each individual under aseptic conditions. DNA extraction was done from whole blood, and PCR was performed. Statistical analysis was performed using Chi-square test and odds ratio (OR) and 95% confidence intervals (CIs).

RESULTS

The results are suggestive that glutathione S-transferase mu1 (GSTM1) null was associated with increased risk of OLP (OR = 5.5, 95% CI = 1.14-26.41, P = 0.021) and OSCC (OR = 11, 95% CI = 1.99-60.5, P = 0.021). Glutathione S-transferase theta1 (GSTT1) null genotype was associated with increased risk of OLP (OR = 2.154, 95% CI = 0.74-26.672, P > 0.99) and OSCC (OR = 2.154, 95% CI = 0.74-26.672, P > 0.99). The glutathione S-transferase mu3 (GSTM3) AB + BB genotypes appear to be risk factors for OSCC (OR = 1.31, 95% CI = 0.31-5.58, P = 0.7) although statistically insignificant.

CONCLUSIONS

Hence to conclude, because of small sample size in the present study, statistically insignificant results were found and this study failed to observe the relationship between GSTM3 and GSTT1 polymorphism and risk of developing OSCC and positive relationship was observed with GSTM1 polymorphism and risk of developing OSCC.