Adult 1 Buccal exfoliated cells 1 Cell Nucleus 1 Cross-Sectional Studies 1 Feulgen stain 1 Humans 1 Male 1 Micronuclei, Chromosome-Defective 1 Middle Aged 1 Mouth Mucosa 1 Nitrosamines 1 Prospective Studies 1 Time Factors 1 Tobacco 1 adult cell nucleus 1 chemically induced 1 chemistry 1 cross-sectional study cytology 1 drug effect 1 genotoxicity 1 human 1 male 1 micronucleus 1 middle aged 1 mouth mucosa 1 nitrosamine 1 pathology 1 prospective study 1