PD-L1 Protein Expression and Gene Amplification Correlate with the Clinicopathological Characteristics and Prognosis of Lung Squamous Cell Carcinoma

Zhenwen Chen,1,2,&ast; Ning Zhao,1,&ast; Qi Wang,1 Yanfeng Xi,3 Xiaoai Tian,2 Huiwen Wu,1 Yirong Xu1,2 1Department of Pathology, Fenyang College of Shanxi Medical University, Fenyang, 032200, Shanxi Province, People’s Republic of China; 2Department of Pathology, Shanxi Fenyang Hospital, Fenyang, Shanxi Province, People’s Republic of China; 3Department of Pathology, Shanxi Cancer Hospital (Shanxi Institute of Oncology), Taiyuan, Shanxi Province, People’s Republic of China&ast;These authors contributed equally to this workCorrespondence: Huiwen Wu; Yirong XuDepartment of Pathology, Fenyang College of Shanxi Medical University, No. 16 Xueyuan Road, Fenyang, 032200, Shanxi Province, People’s Republic of ChinaTel +86 151 3588 2981Email yirongxu@163.comPurpose: To investigate PD-L1 protein expression and gene amplification in lung squamous cell carcinoma (LUSC) and analyse their correlation with the clinicopathological characteristics and prognosis of LUSC patients.Patients and Methods: Tissue samples from 164 LUSC patients were collected. PD-L1 protein was detected by immunochemistry (IHC), and PD-L1 gene amplification was investigated by fluorescence in situ hybridization in LUSC patients.Results: The positive expression rate of PD-L1 in LUSC was 47.6% (78/164), and the amplification rate of PD-L1 was 6.7% (11/164); both rates were higher than those of paratumor tissue. Both PD-L1 positive expression and gene amplification were correlated with clinical stage and lymph node metastasis (P< 0.05). PD-L1 protein expression, PD-L1 gene amplification, late stage, lymph node metastasis and distant metastasis were significantly correlated with the prognosis of patients. Among these factors, late stage, lymph node metastasis, PD-L1 protein expression and PD-L1 gene amplification were independent prognostic factors for LUSC.Conclusion: Positive PD-L1 protein expression and gene amplification are involved in the malignant progression and metastasis of LUSC. Both PD-L1 protein expression and gene amplification are associated with poor prognosis.Keywords: PD-L1 protein expression, PD-L1 gene amplification, lung squamous cell carcinoma, prognosis