Abstract 3989: Different expression and prognostic effect of PD-L1/PD-1 in SCC and non-SCC of non-small cell lung cancer

Abstract

Abstract Although checkpoint inhibitors targeting PD-1/PD-L1 pathway have demonstrated similar clinical activity in treatment of NSCLC both for squamous(SCC) and non-squamous carcinoma (non-SCC) patients, the predictive role of PD-L1 expression is distinct between two histologies in clinical trials. In order to investigated the expression and prognostic roles of PD-1/PD-L1, data from TCGA and GEO database were analyzed and further validated with our original data by IHC in 133 resected NSCLC tumor tissue(49 SCC and 84 non-SCC). Through the analysis of online data, we concluded that PD-L1 expression in SCC was significantly higher than that of non-SCC. In addition, in non-SCC, PD-L1 was associated with immune response and indicated worse prognosis while no such results were observed in SCC. Further, our original data demonstrated PD-L1 expression in tumor cells(TC) and immune cells(IC) were significantly more often and more intense in SCC(P<0.001). In survival analysis, PD-L1 expression in TC and IC were associated with shorter overall survival in non-SCC (P=0.019 and 0.003, respectively). However, in SCC, PD-L1 did not demonstrate any significant effect neither in TC or IC (P=0.526 and 0.674, respectively) which consistent with online data. Contrary to PD-L1, no significant differences of PD-1 expression in tumor infiltrating lymphocytes(TILs) were showed between two histologies. PD-1 in TILs of SCC correlated with worse prognosis (P=0.025) while in non-SCC there was no correlation(P=0.986). Taken together, these findings suggest distinct regulation mechanisms and clinical significance of PD-L1/PD-1 pathway in NSCLC subgroups. Citation Format: Yunpeng Liu, Shuo Wang, Xiujuan Qu, Zhi Liu, Xiaofang Che, Xu Ling, Kezuo Hou, Yibo Fan, Na Song, Ti Wen, Ce Li. Different expression and prognostic effect of PD-L1/PD-1 in SCC and non-SCC of non-small cell lung cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3989. doi:10.1158/1538-7445.AM2017-3989