等位基因特异性PCR法对血液和肿瘤组织EGFR基因突变的比较

Comparison of EGFR mutations in blood and tumor tissue samples by allele-specific PCR

目的采用等位基因特异性PCR法检测肺癌患者循环肿瘤DNA(ctDNA)和肿瘤组织样本中表皮生长因子受体(epidermal growth factor receptor,EGFR)突变,分析两者关系及检测ctDNA EGFR突变的临床应用价值。方法收集22例非小细胞肺癌(non-small cell lung cancer,NSCLC)患者的血液样本和肿瘤组织样本,提取相应血浆游离DNA(cfDNA)和肿瘤组织DNA(tDNA),通过等位基因特异性PCR法分别检测EGFR第18~21号外显子突变,并将两种样本结果进行比较分析。结果 22例NSCLC中,8例血液样本存在EGFR突变,突变率36.4%(8/22);13例肿瘤组织样本有EGFR突变,突变率59.1%(13/22);16例血液样本和肿瘤组织样本EGFR检测结果完全一致。以tDNA检出结果为标准,ctDNA诊断EGFR基因突变敏感度为61.5%,特异度为100%;与tDNA结果的一致率为72.7%。结论等位基因特异性PCR法检测ctDNA的EGFR基因突变,为无法获取肿瘤组织标本患者提供新的检测机会。

Purpose To explore the clinical application value of allele specific PCR in detection of ctDNA EGFR muta-tions by comparing the epidermal growth factor receptor （EGFR） mutation in tumor tissue specimens and circulating tumor DNA （etDNA） of lung cancer patients by allele-specific PCR. Methods 22 pairs of plasma samples and tumor tissue samples of non-small cell lung cancer （NSCLC） patients were collected and the corresponding cfDNA and tDNA were extracted. The cobas EGFR mutation test v2.0 and cobas EGFR mutation test were used to detected EGFR 18-21 exon mutation, respectively. Resuits Among 22 patients with NSCLC, there were 8 cases of EGFR mutations in plasma samples, so the mutation rate was 36. 4% （8/22）. The presence of EGFR mutations in tumor samples was 13 cases, and the mutation rate was 59. 1% （ 13/ 22）. EGFR mutation status of 16 patients in plasma samples was consistent with tumor tissues. The result of tDNA gene mutations was regarded as the standard. Sensitivity of gene mutations in ctDNA was 61.5% , and specificity was 100%. The concordance rate between result of tDNA and ctDNA was 72.7%. Conclusion Detection of ctDNA EGFR gene mutations by allele-specific PCR provides a new detection opportunity for patients unable to obtain tumor tissue specimens.