CYP1A1、GSTM1和GSTT1基因多态性与甘肃省武威市食管癌易感性的关系

目的探讨甘肃省武威市食管癌组织中生物代谢酶Ⅰ相酶细胞色素（CYPIA1）和Ⅱ相酶谷胱甘肽转硫酶MI（GSTM1）、谷胱甘肽硫转移酶TI（GSTT1）基因多态性与食管癌的关系。方法采用PCR-RFLP、multiplex—PCR方法检测216例正常对照f血液）和189例食管癌组织中代谢酶基因CYPIA1和GSTM1、GSTT1的多态性。结果食管癌病例组与正常对照组中：CYP1A1基因MspⅠ酶切位点多态性的频率分别为74．1％和67．6％，差异无统计学意义；GSTM1纯合缺失基因型分别占58．7％和41．2％，差异有统计学意义（P〈0．05），该基因型可能与食管癌易感性的增高有关（OR1．956）；GSTT1纯合缺失基因型分别占51．9％和43．5％，差异无统计学意义，该基因未明显增加对食管癌的易感性（OR1．169）；GSTM1、GSTT1联合缺失基因型在病例组和对照组中的频率分别为38．6％和19．6％，差异有统计学意义（P〈0．05）；同时携带CYPIA1MspⅠ多态突变基因型与GSTM1、GSTT1缺失基因型的个体患食管癌的风险增加（OR2．385，95％CI1．094-3．495）。结论单独的CYP1A1MspI多态突变基因型或者GSTT1缺失基因型与食管癌的易感性不相关；GSTM1纯合缺失基因型及其与GSTT1缺失基因型、CYP1A1MspⅠ多态突变基因型同时存在可增加个体患食管癌的风险，提示GSTM1纯合缺失基因型可能为食管癌发病的易感因素之一，且与其他缺陷基因型存在协同作用。

Relationship between CYP1A1, GSTM1 and GSTT1 genetic polymorphisms and susceptibility of esophageal cancer in Wuwei, Gansu province

Objective To study the genetic polymorphisms of cytochrome P450 （CYP1A1）, glutathione S-transferase M1 （GSTM1）, glutathione S-transferase T1 （GSTT1） and the susceptibility of esophageal cancer in Wuwei, Gansu province. Methods The study was conducted among 189 cases of esophageal cancer and 216 cases of normal controls. The genotypes of the GSTM1 and GSTT1 were detected by multiplex-PCR. Polymorphism of CYP1A1 was detected through PCR- based restriction fragment length polymorphisms （PCR-RFLP）. Results The combined frequencies of T/C and C/C genotype of CYP1A1 in tumors and normal controls were 74.1% and 67.6%, respectively. The differences between patients and normal controls were not statistically significant. The frequencies of GSTM1 null genotype in tumor group （58.7%） were significantly higher than those in controls （41.2%） and this genotype may increase the susceptibility to esophageal cancer （P 〈0.05）. The frequency of GSTT1 null genotype in tumor group was 51.9%, while in controls it was 43.5%. The GSTT1 null genotype did not change the susceptibility to esophageal cancer. The incidence of GSTM1, GSTT1 combined null genotype in tumor group was 38.6%, while in controls it was 19.6%. This different percentage between patients and normal controls was statistically significant （P 〈0.05）. The CYPIA1 gene heterozygous mutation type or homozygous mutation type combined with GSTM1, GSTT1 null genotype increased the risk of esophageal cancer （OR 2.385, 95%CI 1.094-3.495）. Conclusion Both the variation of CYPIA1 gene or GSTT1 null genotype alone may not be related with the susceptibility to esophageal cancer but GSTM1 null genotype alone or combined with GSTT1 null genotype or the 3801 T-C variation of CYP1A1 gene are correlated with esophageal cancer. The results suggest that GSTM1 null genotype alone or in combination with other defective genotypes may serve as risk factors to the esophageal cancer.