湖南地区人群GSTM1和GSTT1基因多态性与结直肠癌遗传易感性分析

Association between Genetic Polymorphism of GSTM1 and GSTT1 and Susceptibility to Colorectal Cancer in Hunan Province

目的探讨代谢酶GSTM1和GSTT1基因多态性与湖南地区人群结直肠癌遗传易感性之间的关系。方法采用以医院为基础的病例-对照研究,应用PCR方法对108例结直肠癌患者和215例正常人群的GSTM1和GSTT1基因型进行检测和分析。结果 GSTM1基因在结直肠癌组和对照组中的缺失率分别为64.8%和48.8%,且两组之间差异具有统计学意义(P<0.05),以GSTM1(+)为参照,GSTM1(-)者结直肠癌发病风险增加2.6倍。GSTT1基因在结直肠癌组和对照组中的缺失率分别为55.6%和45.6%,两组之间差异无统计学意义(P>0.05)。GSTM1和GSTT1基因型之间可能存在联合作用,同时携带GSTM1(-)和GSTT1(-)者比同时携带GSTM1(+)和GSTT1(+)者结直肠癌发病风险增加3.88倍。GSTM1(-)和GSTT1(-)与吸烟在结直肠癌的发病中具有协同作用,与不吸烟者比较,其OR值分别为7.76和6.24。结论 GSTM1基因缺失与本地区人群结直肠癌发病风险相关,GSTT1基因缺失与本地区人群结直肠癌发病风险无关,GSTM1和GSTT1同时缺失者结直肠癌发病风险更高,GSTM1和GSTT1基因缺失与吸烟在结直肠癌的发病中具有协同作用。

Objective To evaluate the association between genetic polymorphism of GSTM1 and GSTT1 and susceptibility to colorectal cancer in Hunan province. Method It was a hospital-based case-control study. Genotypes of GSTM1 and GSTT1 were detected using PCR technique from 108 cases with colorectal cancer and 215 healthy controls. Results The frequencies of GSTM1-null genotype were 64.8% in case group and 48.8% in control group, and significant difference between these two groups was observed. Compared with GSTM1（＋） genotype, persons with GSTM1（-） genotype had 2.6-fold increased risk for developing colorectal cancer. The frequencies of GSTT1-null genotype were 55.6% in case group and 45.6% in control group, and no significant difference between these two groups was observed. The GSTM1 and GSTT1 may had combined action, persons with both GSTM1（-） and GSTT1（-） genotypes had 3.88-fold increased risk for developing colorectal cancer than those with both GSTM1（＋） and GSTT1（＋） genotypes.GSTM1（-） genotype or/and GSTT1（-） genotype interacted with smoking in the carcinogenesis process of colorectal cancer （OR=7.76 and 6.24）. Conclusion These results suggested that GSTM1-null genotype may associate with the risk of colorectal cancer, but GSTT1-null genotype is not associated with the risk of colorectal cancer. Persons with both GSTM1（-） and GSTT1（-） genotypes may be associated with the risk of colorectal cancer. GSTM1（-） genotype or/and GSTT1（-） genotype interacted with smoking in the carcinogenesis process of colorectal cancer.