亚甲基四氢叶酸还原酶基因多态性与非小细胞肺癌化疗敏感性的关系

Genetic polymorphisms in methylenetetrahydrofolate reductase and clinical response to chemotherapy in non-small cell lung cancer

背景与目的 亚甲基四氢叶酸还原酶（MTHFR）是叶酸代谢的关键酶，在DNA甲基化中起重要作用。体外研究已经证明一些基因的异常甲基化可以影响肿瘤细胞对细胞毒性药物和干扰DNA合成药物的敏感性。本研究旨在观察MTHFR基因C677T、A1298C多态与非小细胞肺癌（NSCLC）患者对铂类药物为基础的化疗方案敏感性的关系。方法 收集经病理学确诊的中、晚期NSCLC病例97例。用PCR—RFLP技术检测患者MTHFR基因型。所有患者均经以铂类为基础的化疗方案治疗。结果 ①97例NSCLC病例中，MTHFRC677TC／C、C／T和T／T基因型频度分别为34．0％、50．5％和15．5％，A1298CA／A、A／C和C／C基因型频度分别为64．6％、29．2％和6．2％。化疗后总有效率（完全缓解＋部分缓解）为39．2％。②分别分析MTHFRC677T多态性和A1298C多态性与化疗疗效的关系时，未发现这两个多态与NSCLC化疗的疗效有明显关系。而联合分析MTHFRC677T多态性A1298C多态基因型与化疗疗效的关系时，发现携带MTHFRC677TT等位基因（C／T或T／T基因型）、同时携带A1298CA／A基因型者的有效率为51．1％，显著高于同时携带C677TC／T基因型及A1298CC等位基因者（12．5％）（P=0．007，OR=7．30，95％CI：1．34～52．47）。结论 MTHFR基因C677T和A1298C多态联合作用可影响NSCLC对化疗的敏感性，MTHFR基因型检测对指导NSCLC的化疗、预测疗效具有较高的临床价值。

Background and objective Methylenetetrahydrofolate reductase （MTHFR） plays an important role in metabolism of folate and DNA methylation. In vitro, many studies have demonstrated that abnormal methylation of some genes may affect the sensitivity of tumor cells to cytotoxic drugs and agents interfering with DNA synthesis. The aim of this study is to investigate the relationship between genetic polymorphisms of MTHFR C677T or A1298C and the response to platinum-based chemotherapy in non-small cell lung cancer （NSCLC）. Methods A total of 97 patients with NSCLC were analyzed. MTHFR genotypes were detected in all the patients by PCR-RFLP method. All the patients were treated with platinum-based chemotherapy. Resuits （1） Out of all the cases, the frequencies of MTHFR C677T C/C, C/T and T/T genotypes were 34.0% , 50.5% and 15.5%, respectively, while the frequencies of MTHFR A1298C A/A, A/C and C/C genotypes were 64.6%, 29.2% and 6.3%, respectively. The overall response rate （complete and partial response） to platinum-based chemotherapy was 39.2%. （2） No significant difference in response rate to chemotherapy was observed according to the MTHFR C677T or A1298C genotypes. However, MTHFR C677T and A1298C polymorphisms showed a synergic effect on chemotherapeutic efficacy, the response rate of patients with MTHFR C677T T allele and A1298C A/A genotype （51.1% ） was significantly higher than those wi.th MTHFR C677T C/Tand A1298C C allele （12. 5%）（P=0. 007, OR=7. 30, 95% CI： 1. 34-52. 47）.Conclusion The results suggest that the synergic effect between MTHFR C677T and A1298C polymorphisms is associated with clinical response to platinum-based chemotherapy. Detection of MTHFR genotypes may indicate the sensitivity of NSCLC patients to platinum-based chemotherapy.