J Cancer 2017; 8(9):1579-1585. doi:10.7150/jca.18729

Research Paper

Association between PD-L1 Expression on Tumour-Infiltrating Lymphocytes and Overall Survival in Patients with Gastric Cancer

Wenfeng Fang1, 2, 3, Ying Chen4, Jin Sheng1, 2, 3, Ting Zhou1, 2, 3, Yaxiong Zhang1, 2, 3, Jianhua Zhan1, 2, 3, Lin Liu4, Jiaxing Huang4, Peijian Peng4✉, Li Zhang1, 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. Department of Medical Oncology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhu Hai, China.

Abstract

Purpose Targeting of the PD-1/PD-L1 signalling pathway is a promising treatment strategy in several cancers. The aim of this study was to assess the expression of PD-L1 on tumour cells and tumour-infiltrating lymphocytes (TILs) in gastric cancer (GC) and its prognostic impact.

Materials and Methods A total of 240 patients who were diagnosed with GC at Sun Yat-sen University Cancer Centre (SYSUCC) from May 2008 to December 2013 were included in this study. PD-L1 expression was detected by immunohistochemistry (IHC) in all GC tumour specimens. The Cox proportional hazard regression model was used to assess the association between PD-L1 expression and overall survival (OS).

Results The positive rates of PD-L1 expression on tumour cells and TILs were 74.8% and 65.8%, respectively. Patients with poor tumour differentiation had higher positive rates of PD-L1 expression on tumour cells (p=0.023). There was no significant association between PD-L1 expression on tumour cells and other clinicopathological data. In TILs, PD-L1 expression was significantly higher in patients who underwent surgery (p=0.031) and were in the late stage (p=0.021) than those without surgery and in the early stage. Patients with positive PD-L1 expression on TILs had a significantly shorter five-year OS than those with negative PD-L1 expression (14.2 vs 18.3; p=0.001); therefore, PD-L1 expression on TILs is an independent prognostic factor. However, PD-L1 expression on tumour cells is not associated with OS (p=0.945).

Conclusion Our findings suggest that PD-L1 expression on TILs may be a predictive factor for immunotherapy of PD-1/PD-L1 pathway inhibitors.

Keywords: gastric cancer, PD-L1, TILs.

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How to cite this article:
Fang W, Chen Y, Sheng J, Zhou T, Zhang Y, Zhan J, Liu L, Huang J, Peng P, Zhang L. Association between PD-L1 Expression on Tumour-Infiltrating Lymphocytes and Overall Survival in Patients with Gastric Cancer. J Cancer 2017; 8(9):1579-1585. doi:10.7150/jca.18729. Available from http://www.jcancer.org/v08p1579.htm