Effect of CD274 (PD-L1) overexpression on survival outcomes in 10 specific cancers: a systematic review and meta-analysis

Aim: The prognostic role of CD274 (programmed cell death ligand 1 (PD-L1)) overexpression has been examined in many studies. However, the results are controversial and conflicting. The present study aims to investigate the potential role of CD274 (PD-L1) immunohistochemical overexpression as a prognostic marker in malignant tumours. Methods: We searched PubMed, Embase and Web of Science from inception to December 2021 to identify potentially eligible studies. The pooled HRs with 95% CIs were calculated to identify the association between CD274 (PD-L1) overexpression and overall survival (OS), cancer-specific survival, disease-free survival, recurrence-free survival and progression-free survival in 10 lethal malignant tumours. Heterogeneity and publication bias were also analysed. Results: The study included 57 322 patients from 250 eligible studies (241 articles). The meta-analysis by tumour type using multivariate HR revealed worse OS in non-small cell lung cancer (HR 1.41, 95% CI 1.19 to 1.68), hepatocellular carcinoma (HR 1.75, 95% CI 1.11 to 2.74), pancreatic cancer (HR 1.84, 95% CI 1.12 to 3.02), renal cell carcinoma (HR 1.55, 95% CI 1.12 to 2.14) and colorectal cancer (HR 1.46, 95% CI 1.14 to 1.88). Estimated HRs showed associations between CD274 (PD-L1) overexpression and worse prognosis across different types of tumours in various survival endpoints, but no inverse correlation was identified. The heterogeneity for most of the pooled results was high. Conclusions: This large meta-analysis suggests that CD274 (PD-L1) overexpression is a potential biomarker for multiple types of cancers. However, further studies are needed to reduce high heterogeneity. Prospero registration number: CRD42022296801.