BackgroundLittle research has been done on clinicopathological characteristics and human papillomavirus (HPV) status of anogenital and oropharyngeal squamous cell carcinomas (SCC) with a strong expression of programmed death ligand 1 (PD-L1) in tumor cells. Therefore, we conducted this meta-analysis.MethodsWe performed a comprehensive research in PubMed, Embase and Cochrane databases up to September 30th, 2019. The effect size was hazard ratio (HR) with 95% confidence interval (CI) for overall survival (OS), cancer specific survival (CSS), disease free survival (DFS). The pooled odds ratio (OR) with 95%CI were used to assess the association between PD-L1 expression and clinicopathological features along with HPV status.ResultsA total of 2003 cases (944 anogenital and 1059 oropharynx SCC patients) were included. High PD-L1 expression in anogenital SCC cases were associated with advanced age (OR=1.63, 95%CI:1.04-2.58) and HPV negativity (OR=0.47,95%CI:0.31-0.71). Besides, PD-L1 positive anogenital SCC cases held a significant declined OS (HR=2.18, 95%CI:1.37-3.47) and CSS (HR=2.45, 95%CI:1.30-4.65). For oropharynx SCC, PD-L1 was more frequent in younger and HPV positive patients (OR=0.60, 95%CI:0.37-0.98; OR=3.01, 95%CI:1.78-5.09) and PD-L1 expression was relevant to better OS and DFS (HR=0.76, 95%CI:0.60-0.97; HR=0.50, 95%CI:0.33-0.75).ConclusionsThe meta-analysis demonstrated that in anogenital SCC, PD-L1 positivity had to do with a worse outcome, which might attribute to advanced age, higher tumor grade, lymph node metastasis and HPV negativity, while in oropharynx cancer, PD-L1expression was related to better prognosis for the reason that PD-L1 was less frequent in the aged and negative HPV status.