二磷酸尿苷葡萄糖苷转移酶1A7基因多态性与国人结直肠癌的相关性研究

The association of genetic polymorphisms of UDP-glucuronosyltransferase 1A7 gene with colorectal cancer in Chinese

目的探讨二磷酸尿苷葡萄糖苷转移酶(UGT)1A7基因第1外显子3处单核苷酸多态性与国人结直肠癌(CRC)的相关性,及其在我国自然人群中的分布频率。方法采用人群为基础的成组匹配病例对照研究,以半巢式聚合酶链反应(PCR)、等位基因特异PCR和PCR-限制性内切酶片段长度多态性(RFLP)联用分析技术对140例CRC患者和280例正常对照者的UGT1A7基因型进行检测分析。结果CRC患者携带变异等位基因(~*2,~*3,~*4)频率明显高于对照组(50．0%比38．6%,P＜0．01)。CRC患者携带变异纯合基因型频率(28．6%)明显高于对照组(14．3%),差异有统计学意义(P＜0．01)。与野生型相比,变异杂合型及纯合型OR比值增高趋势有统计学意义(X^2=12．15,P＜0．01)。红烧熏炸食品摄入与CRC发病有关,与低摄人量组(≤5．40 kg/年)相比,中(≤14．35kg/年)、高(＞14．35kg/年)摄入量组风险明显增高,在中摄入量组风险增高差异有统计学意义(P＜0．05,OR=1．84,95% CI∶1．09～3．11)。以红烧熏炸、腌制食品摄人以及吸烟、饮酒状况为分层因素,分析UGT1A7基因多态性与CRC发病的相关性,仅在吸烟个体观察到有相关效应,差异有统计学意义(P＜0．05,OR=3．13,95%CI∶1．03～9．52),在饮酒个体观察到的相关效应临界于显著性水平(P=0．05,OR=2．89,95%CI∶0．99～8．46)。结论UGT1A7基因多态性与CRC的发病呈正相关关系,同时与吸烟、饮酒等环境危险因素可能存在一定的协同作用。

Objective To investigate the allele frequency distribution of UDP-glucuronosyltransferase （UGT） 1A7 gene and its association with risk of colorectal cancer （CRC） in Chinese. Methotis One hundred and forty cases of CRC and 280 controls matching from the same follow-up cohort population established in 1989 were enrolled. The polymerase chain reaction （PCR）-based genotyping techniques including semi-nested PCR, allele-specific PCR and PCR-restriction fragment length polymorphism （RFLP） were used for analysis of UGTIA7 polymorphism. Results The variant allele frequency in CRC cases was significantly higher than that in controls （50.0% and 38.6%, respectively）. On variant genotypes analysis, the frequency of variant homogenotes in CRC patients （28.6 %） was also significantly higher than that incontrols （14.3 % ）, which exhibited a significant association with CRC risk （OR 2.74, 95%CI： 1.54 - 4.88）. The tendency tested by likelihood ratio suggested that the increase of risk had statistical significance （x^2= 12.15, P = 0.00）. As for the environmental exposure factors, the fried or smoked-dried meat consumption was associated with CRC, and the risk increased significantly in moderate （≤14. 35 kg/year） and high （〉14. 35 kg/year） intake groups compared with that in low intake （45.40 kg/year） group （P = 0.02, OR = 1.84, 95%CI ： 1.09 - 3.11）. Stratification analysis by environmental factors found only in previous-current cigarette smoking individuals or in previous current alcohol drinking individuals, the variants were significantly associated with CRC （OR = 3.13, 95%CI： 1.03 -9.52, OR = 2.89, 95%CI： 0.99-8.46, respectively）. Conclusions UGT1A7 poly morphisms was positively related with occurance of CRC, which also exerted a synergetic effects with environmental factors, cigarette smoking and alcohol consumption.