The association between PD-L1 and EGFR status and the prognostic value of PD-L1 in advanced non-small cell lung cancer patients treated with EGFR-TKIs

// Yanna Tang 1,2,3 ,* , Wenfeng Fang 1,2,3 ,* , Yaxiong Zhang 1,2,3 ,* , Shaodong Hong 1,2,3 , Shiyang Kang 1,2,3 , Yue Yan 1,2,3 , Nan Chen 1,2,3 , Jianhua Zhan 1,2,3 , Xiaobo He 1,2,3 , Tao Qin 1,2,3 , Ge Li 4 , Wenyi Tang 5 , Peijian Peng 5 and Li Zhang 1,2,3 1 Department of Medical Oncology, Sun Yat-sen University Cancer Center, Guangzhou, China 2 State Key Laboratory of Oncology in South China, Guangzhou, China 3 Collaborative Innovation Center for Cancer Medicine, Guangzhou, China 4 Key Laboratory for Stem Cells and Tissue Engineering, Sun Yat-sen University, Guangzhou, China 5 Department of Medical Oncology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhu Hai, China * These authors have contributed equally to this work Correspondence to: Li Zhang, email: // Peijian Peng, email: // Keywords : NSCLC, PD-L1, EGFR status, TKI, prognosis Received : January 08, 2015 Accepted : March 01, 2015 Published : March 29, 2015 Abstract Backgrounds: Recent clinical trials have shown that immune-checkpoint blockade yields remarkable response in a subset of non–small cell lung cancer (NSCLC) patients. However, few studies directly focus on the association between epidermal growth factor receptor (EGFR) mutational status and programmed cell death-ligand 1 (PD-L1) expression. We examined whether PD-L1 is related to clinicopathologic factors and prognosis in patients with advanced NSCLC treated with EGFR-tyrosine kinase inhibitors (EGFR-TKIs). Methods: One-hundred and seventy patients with advanced NSCLC were explored. Paraffin-embedded tumour sections were stained with PD-L1 antibody. EGFR mutation was examined by fluorescent quantitative polymerase chain reaction (PCR). The correlations between PD-L1 expression and EGFR status and survival parameters were analyzed. Results: The overall frequency of PD-L1 over-expression was 65.9% (112/170). In lung adenocarcinoma, PD-L1 tended to be associated with mutant EGFR (PD-L1 overexpression in mutant and wild-type EGFR, 64/89 (71.9%) vs. 32/56 (57.1%), respectively; p=0.067). Subgroup analyses showed that high PD-L1 expression was associated with significantly shorter overall survival (OS) in EGFR wild-type patients (p=0.029) but not in EGFR mutant patients (p=0.932) treated with EGFR-TKIs. Even more, for EGFR mutant patients, higher expression of PD-L1 might only signal better outcome with TKIs. Conclusions: High PD-L1 expression was likely to be associated with the presence of EGFR mutation in advanced lung adenocarcinoma. For EGFR wild-type patients, the PD-L1 over expression can be considered as a poor prognostic indicator of OS.