Background: Pembrolizumab, an immunotherapy for advanced non-small cell lung cancer (NSCLC), needs to predict treatment response based on test results including immunohistochemistry (IHC), which detects the expression of programmed death ligand 1 (PD-L1). The aim of this study was to evaluate the feasibility of immunocytochemistry (ICC) in NSCLC cytology to detect PD-L1 and to investigate the correlation between PD-L1 expression and clinical pathology and molecular features.
Methods: Sixty cases of lung adenocarcinoma pleural cytology were collected and PD-L1 sp263 reagent was used for immunocytochemical staining according to the manufacturer's instructions. Next-generation sequencing (NGS) was performed on pleural cytology specimens to explore its correlation.
Results: Of the 60 cases of lung adenocarcinoma pleural effusion cell block, 35 cases were positive for PD-L1 expression, and the positive expression rate was 58.3%. The positive rate of PD-L1 expression in the specimens of our hospital was 33.3%, and there was no significant difference between the cytological specimens and the histological specimens (P>0.05). Of the 60 cytological specimens, 26 were tested for NGS, and 15 (57.7%) were found to have epidermal growth factor receptor (EGFR) mutations. No correlation was found between PD-L1 expression and EGFR mutation. The positive expression rate of PD-L1 were not correlated with the age and gender in the study population (P>0.05).
Conclusions: When no surgical specimens are available, pleural cytology cell block specimens can be used for immunocytochemical detection of PD-L1, and the results are feasible.
【中文题目：肺腺癌胸水标本中PD-L1的蛋白表达与临床病理特征及分子改变的相关性研究】 【中文摘要：背景与目的 非小细胞肺癌的免疫治疗药物pembrolizumab需要基于包括免疫组织化学（immunohistochemistry, IHC）在内的检测结果，即通过检测程序性死亡配体1（programmed cell death protein 1, PD-L1）的表达等手段来预测治疗反应。评估肺腺癌细胞学标本免疫细胞化学（immunocytochemistry, ICC）方法检测PD-L1的可行性，并探讨PD-L1表达与临床病理及分子特征的相关性。方法 收集60例肺腺癌胸水细胞学标本应用PD-L1 sp263试剂按照生产说明书进行免疫细胞化学染色，同时对胸水细胞学标本做高通量二代测序（next-generation sequencing, NGS），探讨PD-L1与驱动基因突变的相关性。结果 60例肺腺癌胸水细胞块标本ICC检测中，有35例PD-L1表达阳性，阳性表达率为58.3%。本院57例组织学标本PD-L1 IHC表达的阳性率为33.3%，细胞学标本与组织学标本差异无统计学意义（P>0.05）。60例细胞学标本中26例接受NGS检测，15例（57.7%）发现表皮生长因子受体（epidermal growth factor receptor, EGFR）突变，经统计PD-L1表达与EGFR突变未发现相关性。PD-L1的阳性表达率与研究人群的年龄、性别、是否淋巴结或远处转移及是否进行放化疗或靶向治疗均未发现相关性（P>0.05）。结论 在无手术标本可取时，胸水细胞学细胞块标本可以对PD-L1进行免疫细胞化学检测，其结果具有可行性。】 【中文关键词：程序性死亡配体1；免疫细胞化学；肺腺癌；胸水细胞块；二代测序】.
Keywords: Immunocytochemistry; Lung adenocarcinoma; Next-generation sequencing; Pleural effusion cell block; Programmed death ligand 1.