OBJECTIVE: To analyze chromosomal aberrations (CA) as an index of DNA damage, to measure DNA repair capability using mutagen sensitivity assay and to correlate tobacco exposure with CA. STUDY DESIGN: Oral cancer patients, healthy tobacco chewers and healthy tobacco nonusers were studied for spontaneous and mutagen-induced CA. An arbitrary unit obtained for lifetime tobacco exposure (LTE) was compared with CA. RESULTS: Mean levels of spontaneous and mitomycin-C-induced CA were higher in patients as compared to chewers and controls. DNA repair capability of patients was significantly deficient (p < or = 0.016) as compared to that of chewers. LTE was significantly higher (p = 0.004) in patients than chewers. Chewers having high LTE and spontaneous CA above cutoff levels might be at a greater risk of oral carcinogenesis. CONCLUSION: There is a probable risk of oral carcinogenesis in healthy tobacco consumers having higher CA and LTE. Whether the deficient DNA repair capacity of oral cancer patients is due to the disease process or the tobacco exposure needs to be confirmed with a larger population study.
OBJECTIVE: To analyze chromosomal aberrations (CA) as an index of DNA damage, to measure DNA repair capability using mutagen sensitivity assay and to correlate tobacco exposure with CA. STUDY DESIGN:Oral cancerpatients, healthy tobacco chewers and healthy tobacco nonusers were studied for spontaneous and mutagen-induced CA. An arbitrary unit obtained for lifetime tobacco exposure (LTE) was compared with CA. RESULTS: Mean levels of spontaneous and mitomycin-C-induced CA were higher in patients as compared to chewers and controls. DNA repair capability of patients was significantly deficient (p < or = 0.016) as compared to that of chewers. LTE was significantly higher (p = 0.004) in patients than chewers. Chewers having high LTE and spontaneous CA above cutoff levels might be at a greater risk of oral carcinogenesis. CONCLUSION: There is a probable risk of oral carcinogenesis in healthy tobacco consumers having higher CA and LTE. Whether the deficient DNA repair capacity of oral cancerpatients is due to the disease process or the tobacco exposure needs to be confirmed with a larger population study.