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

Abstract

Purpose

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

Abbreviations

LUSC, lung squamous cell carcinoma; IHC, immunochemistry; NSCLC, non-small-cell lung cancer; SCLC, small cell lung cancer; UICC, Union for International Cancer Control; TMAs, Construction of tissue microarrays; ASL48, Autostainer Link 48; FISH, Fluorescence in situ hybridization; DFS, Disease-free survival; OS, Overall survival; PD-1, Programmed death receptor-1; PD-L1, Programmed cell death ligand 1; HR, hazard ratio.

Author Contributions

Zhenwen Chen, Ning Zhao and Yirong Xu designed the whole study, collected the tissue specimens and performed FISH methods, read the sections and taken the picture of FISH, collected and analyzed data, then wrote the draft paper and revised paper. Yanfeng Xi, Huiwen Wu, Xiaoai Tian and Qi Wang developed the idea for the clinical study, collected clinicopathological data, performed IHC and wrote the materials of draft paper and revised the paper. All authors have reviewed and approved the drafted and final paper. All authors have agreed on the journal to which the article will be submitted and agreed to take responsibility and be accountable for the contents of the article.

Disclosure

The authors report no conflicts of interest in this work.