结直肠癌K-ras基因突变位点的检测及其临床意义

Detection of K-ras gene mutation in colorectal cancer and its clinical significance

目的:探讨结直肠癌中K-ras基因突变状态及其与临床病理特征的关系。方法:应用实时荧光定量PCR(RT-qPCR)和直接基因测序法检测200例结直肠癌患者癌组织K-ras基因突变状态。将两种检测结果进行对比,并结合临床病理资料分析其意义。结果:200例结直肠癌患者中,RT-qPCR检测出突变63例,突变检出率31.5%;经直接基因测序,测序成功的样品169例,检出突变50例,突变检出率29.6%。其中第12密码子GGT→GAT最常见,占34.9%(22/63);其次是第13密码子GGC→GAC,占28.6%(18/63);第12密码子GGT→CGT最少,全组未见(0/63)。两种方法突变检测一致率为98%。K-ras基因突变与肿瘤分化程度有关(P<0.05),而与患者性别、年龄、肿瘤部位、淋巴结转移及TNM分期无明显关系(均P>0.05)。结论:RT-qPCR能快速、敏感、准确地检测结直肠癌K-ras基因突变位点,为临床靶向治疗提供可靠的参考依据。

Objective： To investigate K-ras gene mutation status and its relations with the clinicopathological characteristics in patients with colorectal cancer. Methods. The K-ras gene mutation status in the tumor tissues from 200 colorectal cancer patients were detected by Real-time fluorescence quantitative PCR （RT-qPCR） and direct sequencing, respectively. The results obtained by the two methods were compared and their significance was analyzed in conjunction with the main clinicopathological variables. Results： Of the 200 colorectal cancer specimens, 63 mutation cases were detected by RT-qPCR, and the mutation detection rate was 31.5%; 50 mutation cases were detected from the 169 specimens that were successfully sequenced by direct sequencing technique, and the mutation detection rate was 29.6%. The GGT→GAT at codon 12 was the most prevalent mutation and accounted for 34.9% （22/63） of the total mutation cases, followed by GGC→GAC at codon 13 that accounted for 28.6% （18/63） of the total mutation cases, while GGT-~GCT at codon 12 was the rarest mutation that was not found in any case of the entire group （0/63）. The concordance rate between two methods was 98%. K-ras gene mutation was significantly associated with the differentiation of the tumor （P〈0.05）, but not related to the sex, age, tumor location, lymph node metastasis or TNM stage of patients （all P〉0.05）. Conclusion： RT-qPCR is a rapid, sensitive and accurate method for detection of the K-ras gene mutation, and therefore provides reliable information for clinical applications of targeted therapy.