Background: Considering that tobacco is the main etiological factor in oral cancer and that oral leukoplakia is the most prevalent potentially malignant lesion, together with the fact that GSTT1 polymorphism increases the risk of oral squamous cell carcinoma, the purpose of this study was to investigate the GSTT1 null polymorphism and the risk of oral leukoplakia in individuals with tobacco smoking habits in a Brazilian population.
Materials and methods: The GSTT1 genotypes of 72 tobacco smoking patients with oral leukoplakia and 72 tobacco smoking healthy subjects were studied by PCR-based methods.
Results: The frequency of the GSTT1 null genotype in the group with oral leukoplakia (48.6%) was statistically different from the controls (27.8%). After stratification, the frequencies of the null genotype in female patients, lesions with absent/mild grade of dysplasia and from low-risk sites were statistically different from the control.
Conclusion: The GSTT1 null genotype may increase the risk of developing oral leukoplakia.