【作者】 王涛；

【导师】 孙培春；

【作者基本信息】 郑州大学 ， 外科学（专业学位）， 2023， 硕士

【摘要】 目的探讨PD-L1在MSI和EBV阳性胃癌中的临床病理特征及预后影响。方法收集2020年1月至2021年1月在郑州大学人民医院行D2胃癌根治术的312例患者的临床病理资料,采用免疫组织化学(immunohistochemistry,IHC)检测胃癌组织中程序性死亡配体-1(programmed death-ligand 1,PD-L1)和错配修复(mismatch repair,MMR)蛋白的表达水平。PD-L1表达依据联合阳性评分(combined positive score,CPS),将CPS≥1判定为PD-L1表达阳性,CPS<1判定为PD-L1表达阴性。在MSI表达方面,主要检测肿瘤组织中MLH1、MSH2、MSH6和PMS2四种错配修复蛋白的表达情况,将出现1种MMR蛋白表达缺失定义为微卫星低度不稳定(microsatellite stable-low,MSI-L),出现≥2种MMR蛋白表达缺失为微卫星高度不稳定(microsatellite stable-high,MSI-H),无表达缺失为微卫星稳定(microsatellite stability,MSS)。EB病毒的表达采用原位杂交技术检测胃癌组织内EBV编码的小RNA(EBV-encoded RNA,EBER)表达情况。使用Spearman检验分析胃癌中PD-L1蛋白表达与MSI状态和EBV阳性的相关性,采用卡方检验分析PD-L1、MSI状态和EBV阳性与临床病理特征的关系,并进一步分析MSI胃癌和EBV相关性胃癌(EBV-associated gastric carcinoma,EBVaGC)中PD-L1表达与临床病理特征的关系。采用Kaplan-Meier生存曲线分析MSI胃癌和EBVaGC中PD-L1表达对患者预后的影响,使用Cox单因素和多因素分析影响MSI胃癌和EBVaGC患者的预后因素。结果312例胃癌患者中137例(43.91%)出现PD-L1蛋白表达阳性,且PD-L1表达与TNM分期、淋巴结转移和浸润深度显著相关(P<0.05),Spearman相关分析表明胃癌中PD-L1表达与MSI(x~2=13.339,P<0.01,r=0.207)和EBV阳性(x~2=5.311,P=0.021,r=0.130)呈正弱相关。312例胃癌患者中62例(19.87%)为MSI胃癌,且MSI与肿瘤位置、TNM分期显著相关(P<0.05),进一步分析发现MSI胃癌PD-L1阳性率(64.52%)高于MSS胃癌(38.80%)(P<0.05),且MSI胃癌PD-L1表达与淋巴结转移、浸润深度显著相关(P<0.05)。312例胃癌患者中EBVaGC占8.33%(26/312),且EBV阳性与性别、肿瘤位置和TNM分期密切相关(P<0.05),进一步分析发现EBVaGC中PD-L1阳性率(65.38%)高于EBV阴性者(41.96%)(P<0.05),且EBVaGC中PD-L1表达与分化程度、浸润深度显著相关(P<0.05)。Kaplan-Meier生存曲线显示:MSI胃癌患者2年总生存率为79.02%,尽管PD-L1阳性表达者术后2年生存率(75.0%)低于阴性者(86.36%),但PD-L1表达对并不是MSI胃癌患者预后的影响因素(P>0.05)。Cox单因素分析显示,肿瘤直径、TNM分期、淋巴结转移和脉管内癌栓是影响MSI胃癌的预后因素(P<0.05);Cox多因素分析显示,肿瘤直径和淋巴结转移是MSI胃癌预后的独立影响因素(P<0.05)。EBVaGC患者2年总生存率为73.07%,尽管PD-L1阳性表达者术后2年生存率(70.59%)低于阴性者(77.78%),但PD-L1表达并不是EBVaGC患者预后的影响因素(P>0.05)。Cox单因素和多因素显示,TNM分期是EBV阳性胃癌患者预后的独立影响因素(P<0.05)。结论PD-L1在MSI和EBV阳性胃癌中广泛表达,且存在正相关性。肿瘤直径和淋巴结转移是MSI胃癌患者预后的独立影响因素,TNM分期是EBV阳性胃癌患者预后的独立影响因素,但PD-L1表达并不是影响MSI和EBV阳性胃癌患者的预后因素。更多还原

【Abstract】 ObjectiveTo investigate clinical pathological characteristics and prognosis research of PD-L1 in MSI and EBV positive gastric cancer.MethodsThe clinicopathological data of 312 patients undergoing D2 radical gastrectomy at the People’s Hospital of Zhengzhou University from January 2020 to January 2021were collected,immunohistochemistry(IHC)was used to detect the expression level of programmed death ligand 1(PD-L1)and mismatch repair(MMR)proteins in gastric cancer tissues.Based on the combined positive score(CPS),PD-L1expression was determined to be positive if CPS≥1,and negative if CPS<1.In terms of MSI expression,we mainly detected the expression of MLH1,MSH2,MSH6 and PMS2 mismatch repair proteins in tumor tissues,one type of MMR protein expression deletion is defined as microsatellite stable low(MSI-L),more than two types of MMR protein expression deletion are defined as microsatellite stable high(MSI-H),and no expression deletion is defined as microsatellite stability(MSS).EBV-encoded RNA(EBER)expression in gastric cancer tissue was detected by in situ hybridization.Spearman test was used to analyze the correlation between PD-L1protein expression and MSI status and EBV positive in gastric cancer,chi-square test was used to analyze the relationship between PD-L1,MSI status,EBV positive and clinicopathological characteristics,the relationship between PD-L1 expression and clinicopathological characteristics in MSI type and EBV-associated gastric carcinoma(EBVaGC)was further analyzed.Finally,Kaplan-Meier survival curve was used to analyze the effect of PD-L1 expression in MSI type and EBVaGC on the prognosis of patients.Cox univariate and multivariate analysis affect the prognostic factors of patients with MSI and EBVaGC.Results137(43.91%)of 312 patients with gastric cancer showed positive expression of PD-L1 protein,PD-L1 expression was closely related to TNM stage,lymph node metastasis and invasion depth(P<0.05),spearman correlation analysis showed that the expression of PD-L1 in gastric cancer was weakly positively correlated with MSI(x~2=13.339,P<0.01,r=0.207)and EBV positive(x~2=5.311,P=0.021,r=0.130).62(19.87%)of 312 patients with gastric cancer were MSI type gastric cancer,MSI was significantly correlated with tumor location and TNM stage(P<0.05),further analysis showed that the positive rate of PD-L1 in MSI group(64.52%)was higher than that in MSS group(38.80%)(P<0.05),the expression of PD-L1 in MSI group was significantly correlated with lymph node metastasis and invasion depth(P<0.05).EBVaGC accounted for 8.33%(26/312)of 312 patients with gastric cancer,and EBV positive was closely related to gender,tumor location,and TNM stage(P<0.05),further analysis showed that the positive rate of PD-L1 in EBVaGC(65.38%)was higher than that in EBV-negative group(41.96%)(P<0.05),the expression of PD-L1 in EBVaGC was significantly correlated with the degree of differentiation and the depth of invasion(P<0.05).Kaplan-Meier survival curve shows:in patients with MSI type gastric cancer,the total 2-year survival rate was 79.02%.The 2-year survival rate of PD-L1 positive patients(75%)was lower than that of negative patients(86.36%),but the expression of PD-L1 is not a prognostic factor in patients with MSI gastric cancer(P>0.05).Cox univariate analysis showed that tumor diameter,TNM stage,lymph node metastasis and intravascular tumor thrombus were the prognostic factors of MSI type gastric cancer(P<0.05);Cox multivariate analysis showed that tumor diameter and lymph node metastasis were independent prognostic factors of MSI type gastric cancer(P<0.05).Among EBVaGC patients,the total 2-year survival rate was 73.07%.The 2-year survival rate of PD-L1 positive patients(70.59%)was lower than that of negative patients(77.78%),but the expression of PD-L1 is not a prognostic factor in EBVaGC patients(P>0.05).Cox univariate and multivariate analysis showed that TNM staging was an independent prognostic factor in patients with EBV positive gastric cancer(P<0.05).ConclusionPD-L1 is widely expressed in MSI and EBV positive gastric cancer,and there is a positive correlation.Tumor diameter and lymph node metastasis are independent prognostic factors in patients with MSI type gastric cancer;TNM staging is an independent prognostic factor for EBV positive gastric cancer patients,but the expression of PD-L1 is not a prognostic factor for MSI and EBV positive gastric cancer patients.更多还原