EGFR突变的非小细胞肺癌患者EML4-ALK融合基因的检测及其临床特征分析

Detection of EML4-ALK fusion gene and analysis of its clinical features in NSCLC patients with EGFR mutation

目的:检测EML4-ALK融合基因在表皮生长因子受体(epidermal growth factor receptor,EGFR)突变的非小细胞肺癌(non-small-cell lung cancer,NSCLC)人群中的突变率,并分析其与临床特征的关系。方法:入选的102例NSCLC患者均为中国人,且至少满足以下1个入选条件:女性、不吸烟/少吸烟和肺腺癌。将102例患者的组织标本采用多重逆转录聚合酶链反应(multiplex RT-PCR)的方法检测其EML4-ALK融合基因的突变率;对EML4-ALK阳性患者的组织标本采用DNA扩增后直接测序的方法来检测其EGFR(18～21号外显子)及Kirsten鼠肉瘤基因(Kirsten rat sarcoma,KRAS)(1、2号外显子)的突变情况。结果:102例非小细胞肺癌患者的组织标本,有8例(7.8%)存在EML4-ALK融合基因突变,其中7例为突变体1(variant 1,V1),1例为突变体2(vari-ant 2,V2);这8例EML4-ALK阳性患者组织标本的EGFR(18～21号外显子)及KRAS(1、2号外显子)均为野生型。8例阳性患者中,5例患者的年龄小于总体患者的平均年龄(59±10)岁,占62.5%(5/8);女性患者6例,占75%(6/8);不吸烟患者7例,占87.5%(7/8);腺癌患者5例,占62.5%(5/8)。结论:EML4-ALK融合基因突变代表了NSCLC的一个新的分子亚型,EML4-ALK突变与EGFR及KRAS突变是不共存的。

AIM： To detect the frequency of EML4-ALK fusion gene in non-small-cell lung cancer （NSCLC） patients who had epidermal growth factor receptor （EGFR） mutation, and to analyze the relationship between EML4-ALK fusion gene and clinical features. METHODS： One hundred and two Chinese patients with NSCLC were selected on the basis of one or more of the following characteristics： female, never/light smoking history and adenocarcinoma histology. The EML4-ALK fusion gene was identified by single-tube multiplex RT-PCR. In EML4-ALK-positive samples, exon 18 to 21 EGFR mutations and exon 1 and 2 KRAS （Kirsten rat sarcoma） mutations were detected by DNA direct sequencing after PCR amplification. RESULTS： Eight specimens （7.8%） were identified with EML4-ALK fusion genes from 102 NSCLC tissues. Of all positive cases, 7 were variant 1 （V1） and 1 was variant 2 （V2）. In 8 EML4-ALK-positive samples, exon 18 to 21 EGFR and exon 1 and 2 KRAS were wild-types. Among 8 EML4-ALK-positive cases, 5 cases （5/8, 62.5%） were younger than the mean age. Six cases （6/8, 75%） were female and 7 cases （7/8, 87.5%） were non-smokers. Five cases （5/8, 62.5%） had adenocarcinoma histology. CONCLUSION： EML4-ALK fusion gene defines a new molecular subset of NSCLC with distinct characteristics. The EML4-ALK fusion gene is mutually exclusive to EGFR and KRAS mutations.