Toll样受体4基因启动子单核苷酸多态性对结直肠癌预后的影响

The prognostic significance of single nucleotide polymorphisms of Toll-like receptor 4 gene promoter in colorectal cancer

目的 评估Toll样受体4（TLR4）基因启动子单核苷酸多态性（SNP）对结直肠癌预后的影响.方法 收集277例TNM分期Ⅰ～Ⅳ的结直肠癌患者.PCR扩增产物测序法测定结直肠癌患者外周血DNA的TLR4基因启动子SNP位点rs10983755和ss77136219 SNP的基因型,并计算其单倍体型.患者的总生存（OS）和疾病无进展（PFS）情况采用Kaplan-Meier法计算,单变量log-rank法比较SNP不同的基因型和单倍体型对OS和DFS情况的影响,Cox比例风险模型多变量分析对预后的影响.结果 rs10983755发生G→A突变,其基因型GG、GA和AA的频率分别是37.9%、33.9%和28.2%;ss77136219发生A→G突变,其基因型AA、AG、GG的频率分别是41.2%、27.8%和31.0%.两位点多态性符合Hardy-Weinberg平衡（P〉0.05）,具有较强的连锁不平衡（R=0.58,D′=0.74）,其单倍体型GA、GG、AG和AA频率分别为37.2%、11.5%、22.6%和28.7%.全部结直肠癌患者的5年OS率和PFS率分别为68.4%和60.9%.单变量分析显示,rs10983755和ss77136219不同的基因型均具有明显不同的OS率和PFS率（P〈0.001）.在校正年龄、性别、肿瘤部位、手术方式、组织学分级、TNM分期和辅助化疗后,Cox多变量生存分析显示rs10983755和ss77136219不同的基因型和单倍体型同样具有明显不同的OS和PFS情况（P〈0.05）.结论 TLR4基因启动子的SNP是结直肠癌的独立预后因素.

Objective To evaluate the prognostic significance of single nucleotide polymorphisms （SNP） of Toll - like receptor 4 （TLR4） gene promoter in coiotectal cancer. Methods Genotypes and haplotypes analysis of TLR4 promoter SNP rs10983755 and ss77136219 were performed by the direct sequencing of PCR products using DNA from whole blood of 227 patients with colorectal cancer. The survival estimates were calculated using the Kaplan - Meier method. The differences in overall survival （OS） or progressionfree survival （PFS） according to the different genotypes were compared using log - rank tests. Cox proportional hazard model was used for the multivariate survival analyses. Results Gene mutation of G→A in rs10983755 were identified for three genotype GG, GA and AA, with the frequencies of 37.9%, 33.9% and 28.2%, respectively; while the genotype frequencies of AA, AG and GG in ss77136219 with the mutation of A→G were 41.2%, 27.8% and 31.0%, respectively. The genotype frequencies of rs10983755 and ss77136219 were conformed to Hardy - Weinberg equilibrium （ P 〉 0. 05 ） and exhibited strong linkage disequilibrium （ R = 0. 58, D＇ = 0. 74）. The 5 -year OS and PFS were 68.4% and 60. 9% , respectively. In univariate analysis, all TLR4 gene polymorphisms had significant effect on OS and PFS （P 〈 0. 001 ）. According to multivariate Cox model, adjusted for age, sex, site of tumor, surgical resection, differentiation, stage, and adjuvant chemotherapy, there were significant differences in OS and PFS between rs10983755 and ss77136219 （P 〈0. 05）. Conclusion SNP of TLR4 promoter is independent prognostic factor of colorectal cancer.