Evaluation of DNA Damage in Oral Squamous Cell Carcinoma by Comet Assay

Background: The Comet assay is a technique used to detect DNA damage at the single-cell level. This study aimed to investigate the potential relationship between the histopathological grading of oral squamous cell carcinoma (OSCC) and genotoxicity (DNA damage). Methods: Blood samples were collected from both normal subjects and patients diagnosed with OSCC. Slides prepared for the Comet assay were analyzed using an electrofluorescent microscope with a calibrated eyepiece to measure the total image length and head diameter. DNA tail length was calculated by subtracting the head diameter from the total length. Results: In the evaluation of DNA damage in 26 OSCC patients compared to 10 controls, a significantly higher level of DNA damage was observed in OSCC patients (P < 0.001). When considering different histological grades, the mean DNA damage was found to be highest in poorly differentiated (29.9 μm), followed by moderately differentiated (25.60 μm), and lowest in well-differentiated (23.28 μm) cases. Although differences in the average DNA damage did not reach statistical significance among the histological grades (P > 0.05), all “t” values fell below the critical values at the 5% level, indicating no significant differences between the stages. Conclusions: The extent of DNA damage in OSCC was highest in poorly differentiated cases, followed by moderately differentiated and well-differentiated cases. These findings suggest a potential link between histopathological grading and DNA damage in OSCC.