| Summary: | 碩士 === 中國醫藥大學 === 公共衛生學系碩士班 === 99 === Background : The incidence and mortality of oral cancer have increased quickly in the past five years in Taiwan. For men, oral cancer not only occurs at high incidence but also occurs at an early age. Therefore, if we can detect the oral precancerous conditions early and receive the treatment in time or follow up intensively, then it would be of great help on people’s health and the development of our country''s economy. Some studies have been reported that the association between cigarette smoking, alcohol consumption, betel chewing and the risk of oral cancer and precancerous conditions. When people are exposed to harmful substances, especially aromatic amines and other carcinogenic substances, thses substances will be regulated by N-acetyltransferase (NAT) through activation or detoxication of the carcinogenic metabolic pathway. However, the individual susceptibility to disease at the same exposure is different, the difference may be due to the effect of gene polymorphisms and haplotypes.
Aim : The aim of the present study was to investigate the association between oral precancerous conditions and xenobiotic metabolizing gene NAT1(rs4986990 G>A、rs15561 A >C)、NAT2 (rs1041983 C>T codon 94、rs1799930 G>A codon 197、rs1799931 G>A codon 286) polymorphisms and haplotypes,and to evaluate the gene-gene and gene-environment interactions in oral precancerous conditions.
Methods : We conducted a matched case-control study and the participants in present study were adult males who were enrolled from October 2007 to May 2009. All of participants were examined by otolaryngologist, if participants were diagnosed as the oral precancerous conditions like leukoplakia, erythroplakia, verrucous hyperplasia and oral submucous fibrosis were cases in the study and the others without any oral precancerous conditions and oral cancer were selected by 4 (controls):1 (case) frequency matching with the cases in the same 5-yr age group. The main effects of genetic and environmental factors, the gene-gene and gene-environment interactions on oral precancerous conditions were estimated by logistic regression.
Results : After adjusting for demographic and environmental factors, we found that the trend effect of individual carrying NAT2 risk alleles has reached the statistical significance (p = 0.0475); and the trend effect of the combination of NAT1 and NAT2 risk alleles for oral precancerous conditions was significant (p=0.0092). In the haplotype analysis, individuals carrying an rs4986990 G -rs15561 C - rs1041983 T - rs1799930 G-rs1799931 A haplotype were at a significantly increased risk of oral precancerous conditions (adjusted odds ratio (OR) =2.05, 95% Confidence Interval (CI) =1.09-3.85).
Conclusions: Our results suggest that the number of environmental exposure factor or carrying NAT1 and NAT2 risk alleles may be associated with oral precancerous lesions.
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