TP53及KRAS突变对晚期肺腺癌患者抗PD-1免疫治疗潜在的预测价值

发布时间：2018-08-26 12:33

【摘要】：背景近年来,针对程序性死亡因子1(PD-1)及其配体1(PD-L1)的免疫治疗在非小细胞肺癌中获得了突飞猛进的进展。尽管免疫治疗疗效显著,但仅仅只有一小部分患者可以从中获益,如何选择有效的生物标志物筛选出潜在的获益人群是目前面临的主要问题。值得欣喜的是,近年来研究发现肿瘤突变负荷、DNA错配修复缺陷、肿瘤浸润淋巴细胞数量及肿瘤/免疫细胞PD-L1表达水平可以有效预测PD-1抑制剂的疗效。并且,这些因素之间也存在着彼此相互影响的关系。这些发现给我们提出来另一个问题:是否存在其他生物标志物可以同时影响上述两个或多个预测因素从而可以达到更强的预测价值?方法我们通过利用公共数据库(TCGA、GEO及broad)作为探索集,并用我中心二代测序数据作为验证集,从基因组、转录组及蛋白组进行系统分析。临床免疫治疗疗效与基因突变的相关性分别从既往临床试验结果(MSKCC)和我中心(GLCI)免疫治疗数据进行分析。免疫组化及sanger测序用于相关分子检测。基因富集法(GSEA)对相关信号通路进行分析。结果本研究首先通过运用TCGA及GEO数据库相关信息对肺腺癌常见基因突变(TP53/KRAS/EGFR/STK11)与肿瘤免疫微环境中免疫检查点蛋白PD-L1及肿瘤浸润淋巴细胞进行相关性分析。我们发现了 TP53突变及TP53/KRAS双突变促进肺腺癌组织PD-L1表达、肿瘤淋巴细胞浸润及效应T细胞-IFN-γ信号通路的激活。初步确立了上述突变对肿瘤免疫微环境的影响。进而我们对肿瘤突变负荷及突变谱进行分析,通过从公共数据库的探索集(TGCA和Broad)到我中心二代测序的验证集(GLCI)初步证明了 TP53及KRAS突变与肺腺癌肿瘤突变负荷增加及碱基颠换发生频率增加相关。同时利用基因富集分析发现TP53及KRAS突变通过干扰肿瘤细胞细胞周期调控、DNA复制及DNA损伤修复等过程从而增加肿瘤基因突变发生风险。鉴于上述分子机制上的发现而提出了 TP53及KRAS突变可能是肺腺癌免疫治疗的预测标志物的假设。为了证明上述理论推断,我们首先通过利用公共数据库中既往已发表的免疫治疗临床试验患者信息(MSKCC),初步证明了 TP53及KRAS突变尤其是TP53/KRAS双突变患者其免疫治疗疗效显著优于野生型患者。进而我们又分析了真实世界中(GLCI)免疫治疗患者的临床治疗信息,结果同样提示TP53及KRAS突变患者具有更好的免疫治疗效果。结论我们的研究首次探明了 TP53及KRAS突变对肺腺癌PD-L1表达、肿瘤淋巴细胞浸润及肿瘤突变负荷的影响。并进一步从临床免疫治疗中初步确立了TP53及KRAS突变,尤其是TP53/KRAS双突变对肺腺癌PD-1单抗免疫治疗敏感性增加的预测价值。上述发现对未来筛选免疫治疗有效生物标志物提供了新的思路。
[Abstract]:Background Immunotherapy of programmed death factor 1 (PD-1) and its ligand 1 (PD-L1) has made rapid progress in non-small cell lung cancer (NSCLC) in recent years. Although the efficacy of immunotherapy is remarkable, only a small number of patients can benefit from it. How to select effective biomarkers to select potential beneficiaries is the main problem. It is gratifying to note that recent studies have found that the defect of mismatch repair of tumor mutation load, the number of tumor infiltrating lymphocytes and the expression of PD-L1 in tumor / immune cells can effectively predict the efficacy of PD-1 inhibitors. Moreover, these factors also have a mutual influence on each other. These findings raise another question: is there any other biomarker that can affect two or more of these predictive factors at the same time to achieve greater predictive value? Methods by using the common database (TCGA,GEO and broad) as the exploration set and the second generation sequencing data of our center as the validation set, we systematically analyzed the genome, transcriptome and proteome. The relationship between the efficacy of clinical immunotherapy and gene mutation was analyzed from the results of previous clinical trials (MSKCC) and (GLCI) immunotherapy data of our center. Immunohistochemistry and sanger sequencing were used for the detection of related molecules. The related signal pathways were analyzed by gene enrichment method (GSEA). Results in this study, the correlation between common gene mutation (TP53/KRAS/EGFR/STK11) and immunological checkpoint protein (PD-L1) and tumor infiltrating lymphocytes in tumor immune microenvironment was analyzed by using TCGA and GEO database. We found that TP53 mutation and TP53/KRAS double mutation promoted the expression of PD-L1, tumor lymphocyte infiltration and activation of effector T cell -IFN- 纬 signaling pathway in lung adenocarcinoma. The effect of the above mutation on tumor immune microenvironment was preliminarily established. And then we analyze the mutation load and the mutation spectrum of the tumor. From the exploration set (TGCA and Broad) of the common database to the verification set (GLCI) of the second generation sequencing of our center, it was preliminarily proved that the mutations of TP53 and KRAS were correlated with the increase of mutation load and the frequency of base transversion in lung adenocarcinoma. At the same time, gene enrichment analysis showed that TP53 and KRAS mutations increased the risk of tumor gene mutation by interfering with the process of tumor cell cycle regulation, such as DNA replication and DNA damage repair. In view of the above discovery of molecular mechanism, it is suggested that TP53 and KRAS mutations may be predictive markers of immunotherapy for lung adenocarcinoma. In order to prove the above theoretical inference, We first demonstrated that TP53 and KRAS mutations, especially in patients with double TP53/KRAS mutations, were more effective than wild-type patients by using the previously published information of patients with immunotherapy clinical trials in the public database, and the results showed that TP53 and KRAS mutations, especially in patients with double TP53/KRAS mutations, were significantly better than those in wild type patients. Furthermore, we analyzed the clinical information of (GLCI) immunotherapy patients in the real world. The results also indicated that TP53 and KRAS mutation patients had better immunotherapy effect. Conclusion our study demonstrated for the first time the effects of TP53 and KRAS mutations on PD-L1 expression, tumor lymphocyte infiltration and tumor mutation load in lung adenocarcinoma. Furthermore, the predictive value of TP53 and KRAS mutations, especially TP53/KRAS double mutations, for the increased sensitivity of PD-1 monoclonal antibody to immunotherapy of lung adenocarcinoma was preliminarily established from clinical immunotherapy. These findings provide a new idea for screening effective biomarkers for immunotherapy in the future.
【学位授予单位】：南方医科大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：R734.2

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