白介素-18基因多态性与结直肠癌易感性的关系

目的探讨白介素-18（m-18）基因单核苷酸多态性及其单倍型与结直肠癌易感性之间的关系。方法以170例结直肠癌患者和160名健康对照者为研究对象,应用聚合酶链反应一限制性片段长度多态性（PCR-RFLP）的方法对IL．18基因-137G／C、-607C／A单核苷酸多态性进行基因分型,同时用SHEsis软件分析IL-18基因的连锁不平衡及单倍型频率。结果IL-18基因-607C／A多态性在结直肠癌患者和健康人群中的分布差异无统计学意义（P〉0．05）．而IL-18基因-137G／C多态性在两组人群中的分布差异有统计学意义（P〈0．05）。等位基因频率的相对风险分析显示．C等位基因携带者患结直肠癌的风险是G等位基因的1．814倍（OR=1．814,95％CI：1．246～2．642）。联合基因型分析显示,IL-18基因-137G／C、-607C／A单核苷酸多态性存在着强烈的连锁不平衡（ID＇｜=0．945）,-137C／-607A单倍型频率在结直肠癌患者中显著高于健康人群（P〈0．05）。-137C／-607A单倍型携带者显著增加了结直肠癌的发病风险（OR=1．637,95％CI：1．100～2．437）。结论IL—18基因-137G／C多态性和-137C／-607A单倍型与结直肠癌的发病具有相关性．其中-137C等位基因可能是结直肠癌的遗传易感基因。

Association of the IL-18 gene polymorphism with susceptibility to colorectal cancer

Objective To investigate single nucleotide polymorphisms （SNPs） and haplotypes of interleukin-18（IL-18） gene associated with the susceptibility to colorectal cancer（CRC）. Methods Two SNPs of IL-18 gene promoter -137G/C and -607C/A in 170 patients with CRC and 160 healthy controls matched by age and sex in a Chinese population were analyzed using polymerase chain reaction- restriction fragment length polymorphism （PCR-RFLP） strategy. Frequency of haplotypes and linkage disequilibrium of IL-18 gene in different groups were analyzed by SHEsis programs. Results The distributions of IL-18 gene -607C/A polymorphism did not differ between CRC patients and healthy controls, but IL-18 gene -137G/C polymorphism was significantly different （P〈0.05）. The relative risk of C allele for CRC was 1.814 times of the G allele （OR=1.814,95% CI：1.246-2.642）. Consistent with the results of the genotyping analyses, IL-18 -137G/C and -607C/A polymorphisms showed strong linkage disequilibrium （ID＇｜=0.945）, frequency of the -137C/-607A haplotype in patients with CRC was significantly higher than that in healthy controls （P〈0.05）. The-137C/-607A haplotype was associated with a significantly increased risk of CRC （OR =1.637, 95% CI：1.100-2.437）. Conclusions IL-18 gene -137G/C polymorphism and -137C/-607A haplotype are associated with CRC. -137C allele may be an important genetic susceptibility gene for CRC.