Assessment of DNA damage in leukoplakia patients with different degrees of dysplasia

Abstract

Background: Single cell gel electrophoresis (SCGE) assay also known as comet assay is a rapid and highly sensitive fluorescent molecular technique for detecting various forms of deoxyribonucleic acid (DNA) damage at individual cellular level. Materials and methods: The present study was done to detect the extent of DNA damage in oral leukoplakia (OL) and compare with normal individuals. The sample population was obtained from an outpatient clinic of a tertiary teaching dental institute. A total of 36 consecutive patients with leukoplakia and 10 healthy normal volunteers were recruited for the study and assessed for the extent of DNA damage using SCGE following clinical diagnosis and histological grading. Peripheral blood was obtained by venipuncture and SCGE assay was performed. Mean comet tail length was recorded and analyzed statistically to compare the extent of damage in each group. Results: The mean comet tail length seen in leukoplakia patients with moderate to severe dysplasia was 1.25 ± 0.14 mm while for the control subjects, it was 0.31 ± 0.10 mm. The difference was statistically significant (p = 0.000). On comparing within the grades of leukoplakia, a progressive trend of increasing tail length was observed with increasing grades of dysplasia. Conclusion: Deoxyribonucleic acid damage as measured by SCGE is seen in leukoplakia. A stepwise increase in DNA damage levels from healthy controls, through patients with non-dysplastic epithelium to varying grades of dysplasia has been observed indicating the extent of DNA damage in this high risk group.