DNA damage in peripheral blood leukocytes in tobacco users

AIM: To Quantify the DNA single-stranded breaks in the peripheral blood leukocytes (PBLs) of tobacco-habituated individuals with clinically normal mucosa and patients with oral carcinoma. OBJECTIVES: To evaluate DNA damage levels in PBLs of tobacco-habituated individuals with clinically normal mucosa and patients with oral carcinoma and compare with a control group of healthy volunteers. To evaluate the extent of DNA damage in PBLs using Single Cell Gel Electrophoresis (SCGE) in the above groups. MATERIALS AND METHODS: Patients who were attending the outpatient department were enrolled in this study. A control group of 30 healthy volunteers included in Group I were selected from various age groups who are not tobacco users in any form. Thirty patients with tobacco habituation but with clinically normal mucosa were included in Group II, while 30 tobacco-habituated patients with oral squamous carcinoma were included in Group III. A biopsy was taken from the representative area and confirmed histologically. Intravenous blood samples were collected from all the groups for evaluation of the extent of DNA damage using ethidium bromide-stained slides under fluorescent microscope. The DNA tail length was calculated by subtracting the diameter from the total length. Twenty-five randomly selected cells per slide were analyzed and mean calculated. RESULTS: The mean DNA damage levels in patients with tobacco habits were compared with that of the control group and the results were found to be statistically significant. The mean DNA damage level in PBLs between tobacco-habituated patients with normal mucosa and oral cancer patients was found to be statistically significant. The DNA damage in cancer patients was compared with the control group and the results were found to be statistically significant. CONCLUSION: DNA damage evaluation in PBLs by SCGE technique is a sensitive and reliable indicator of tobacco insult.