Evaluation of DNA Damage in Peripheral Blood Leukocytes in Oral Potentially Malignant and Malignant Disorders by Comet Assay

Purpose: Oral squamous cell carcinoma (OSCC) and potentially malignant disorders (PMD) are associated with DNA damage which can be caused by exposure to carcinogens, genotoxins, or increased oxidative stress. Early detection and assessment of the amount of DNA damage using a biomarker such as a comet assay can prove to be extremely beneficial for the patients. The present study evaluated the efficacy of comet assay in assessing DNA damage in peripheral blood leukocytes (PBLs) in oral potentially malignant and malignant disorders. Materials and Methods: The study included fifty-five patients each of leukoplakia, oral submucous fibrosis (OSMF), and OSCC along with fifty-five healthy individuals as control. The patients with deleterious oral habits were categorized into smokeless, smoked, and mixed habit groups. DNA damage was evaluated by measuring the mean tail length (μm). Results: An increased mean tail length (μm) and higher DNA damage were found in OSCC (22.4335 ± 1.52341), and there was a progressive stepwise increase in mean tail length from control (6.8307 ± 0.84261) to PMD (leukoplakia [13.0022 ± 0.74316]; OSMF [10.6085 ± 0.88140]) to OSCC. Although there was a significant increase in the DNA damage in different habit groups (smokeless [14.9380 ± 5.18516]; smoked [15.4947 ± 4.59589], and mixed [16.3650 ± 5.62407]) compared to controls, there was no significant difference between the habit groups. Conclusion: Thus, comet assay technique can be used as a sensitive and reliable indicator for DNA damage evaluation.