%0 Journal Article %T The prognostic significance of PD-L1 and PD-1 expression in patients with nasopharyngeal carcinoma: a systematic review and meta-analysis %A Chen Chen %A Guan-Nan Wang %A Hui Chang %A Shan Liu %A Shi-Rong Ding %A Shuo-Han Zheng %A Song-Ran Liu %A Xiao-Hui Wang %A Xin Yang %A Ya-lan Tao %A Yun-Fei Xia %A Zi-Lu Huang %J Archive of "Cancer Cell International". %D 2019 %R 10.1186/s12935-019-0863-5 %X The online version of this article (10.1186/s12935-019-0863-5) contains supplementary material, which is available to authorized users %K Nasopharyngeal carcinoma %K PD-L1 %K PD-1 %K Prognostic %K Meta-analysis %U https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6530183/