表皮生长因子受体(EGFR)基因突变是非小细胞肺癌（NSCLC）患者对酪氨酸激酶抑制剂(TKI)靶向治疗预后良好的预测因子。然而仍有部分存在EGFR基因突变的NSCLC患者对EGFR-TKI的治疗不敏感。课题组前期研究提示，TKI治疗的效果可能与肿瘤组织中发生EGFR突变的细胞的比例相关，但这一推测尚缺乏研究支持。平行等位基因特异性序列分析(PASS)技术是近年建立的一种突变基因检测和比例分析的新技术，目前尚未见用于肿瘤相关研究的报道。本项目拟在前期研究基础上系统建立并完善基于PASS技术的EGFR基因突变比例检测的技术平台，然后对接受EGFR-TKI治疗的NSCLC患者的肿瘤组织标本进行检测分析，结合对患者的随访探讨EGFR突变比例与靶向治疗效果的关系，同时通过建立携野生型和突变型EGFR的人NSCLC细胞株的混合培养体系，探讨常用化疗药物及EGFR-TKI对EGFR基因突变比例的影响。

Epidermal growth factor receptor (EGFR) mutation is a positive predictive factor indicating favorable prognosis of non-small cell lung cancer to the targeted therapy of tyrosine kinase inhibitor (TKI). However, there are still some NSCLC patients harboring mutant EGFR gene do not sensitive to EGFR-TKI treatment. Our preliminary researches suggested that the efficiency of TKI therapy might related to the proportion of tumor cells harboring mutant EGFR gene. But this hypothesis is still lack of support. Parallel allele-specific sequencing (PASS) is a new technology for mutant gene detection and mutation proportion assaying, which has not been reported in the field of tumor related researches. In this program, the technology platform of PASS is planned to be constructed and perfected on the basis of our previous studies. Then the tumor tissue samples from NSCLC patients receiving EGFR-TKI therapy are planned to be detected by PASS. The relationship between the efficiency of TKI targeted therapy and the proportion of tumor cells harboring EGFR mutation is planned to be analyzed on the basis of PASS detection and the follow-up study on NSCLC patients. The impacts of commonly used chemotherapy drugs and EGFR-TKI on the proportion of EGFR mutation are also planned to be investigated, by establishing the co-culture system of human NSCLC cell lines harboring wild type and mutant EGFR genes.