三阴性乳腺癌组织中PD-1/PD-L1轴表达与TILs关系及临床病意义

Relationship between expression of PD-1/PD-L1 axis and TILs in triple negative breast cancer tissue and its clinical significance

目的探讨三阴性乳腺癌(TNBC)组织中PD-L1/PD-1轴的表达以及肿瘤浸润性淋巴细胞(TILs)与临床病理特征和预后的关系。方法选取2016年1月至2017年8月我院病理科保存的132例石蜡包埋的女性TNBC组织,采用HE染色分析TILs浸润密度,采用免疫组化染色和免疫组织荧光双染色技术检测PD-1、PD-L1在组织中的表达和TILs表型,并探讨PD-L1^(+)CD4^(+)TILs、PD-L1^(-)CD8^(+)TILs表达与TNBC临床病理特征和总生存(OS)的关系。结果PD-1主要分布于TILs的细胞膜和细胞质中,阳性表达率为44.70%(59/132),而PD-L1主要分布于肿瘤细胞和TILs的细胞膜和细胞质中,阳性表达率为58.33%(77/132)。TNBC组织中PD-L1表达与CD4^(+)TILs、CD8^(+)TILs均有关(P<0.05)。PD-L1^(+)CD4^(+)TILs表达率为86.10%(60/72),与肿瘤直径、TNM分期、淋巴管浸润有关(P<0.05);PD-L1^(-)CD8^(+)TILs表达率为69.12%(47/68),与肿瘤直径、组织学分级、TNM分期、淋巴管浸润和淋巴结转移有关(P<0.05)。不同PD-L1表达的TILs浸润表型与患者OS无关(χ^(2)=0.796,P=0.850;χ^(2)=3.733,P=0.292),多因素Cox风险比例回归模型分析,PD-L1^(-)CD8^(+)TILs浸润是影响TNBC患者OS的独立保护因素(HR=0.853,95%CI=0.659~0.998)。结论PD-L1^(-)CD8^(+)TILs浸润预示着较小的肿瘤直径、低组织学分级、低TNM分期、无淋巴管浸润和无淋巴结转移以及良好的生存预后,为PD-1/PD-L1免疫检查点抑制剂的研究提供新思路。

Objective To investigate the expression of PD-L1/PD-1 axis in triple negative breast cancer(TNBC)tissue and the relationship between tumor infiltrating lymphocytes(TILs)infiltration and clinicopathological features and prognosis.Methods A total of 132 paraffin-embedded female TNBC tissues were collected from the department of pathology in our hospital from January 2016 to August 2017.The infiltration density of TILs was analyzed by HE staining,and the expression of PD-1 and PD-L1 in tissues and the TILs phenotype were detected by immunohistochemical staining and immunohistofluorescence staining.The relationship between the expression of PD-L1^(+)CD4^(+)TILs and PD-L1^(-)CD8^(+)TILs and the clinicopathological characteristics of TNBC and overall survival(OS)was investigated.Results PD-1 was mainly distributed in the cell membrane and cytoplasm of TILs with a positive expression rate of 44.70%(59/132),while PD-L1 was mainly distributed in the cell membrane and cytoplasm of tumor cells and TILs with a positive expression rate of 58.33%(77/132).The expression of PD-L1 in tissues was correlated with CD4^(+)TILs and CD8^(+)TILs(P<0.05).The expression rate of PD-L1^(+)CD4^(+)TILs was 86.10%(60/72),which was correlated with tumor diameter,TNM stage and lymphatic infiltration(P<0.05).The expression rate of PD-L1^(-)CD8^(+)TILs was 69.12%(47/68),which was correlated with tumor diameter,histological grade,TNM stage,lymphatic infiltration and lymph node metastasis(P<0.05).The infiltration phenotype of TILs with different PD-L1 expression was not correlated with OS(P=0.850;P=0.292).Multivariate Cox proportional regression model showed that infiltration of PD-L1^(-)CD8^(+)TILs was an independent protective factor for OS of TNBC patients(HR=0.853,95%CI=0.659-0.998).Conclusion PD-L1^(-)CD8^(+)TILs infiltration indicates small tumor diameter,low histological grade,low TNM stage,no lymphatic infiltration or lymph node metastasis,and good survival prognosis,which provides a new idea for the study of immune checkpoint inhibitors for PD-1/PD-L1.