Prognostic and clinicopathological utility of PD-L2 expression in patients with digestive system cancers: A meta-analysis

Abstract

ObjectiveProgrammed death ligand-2 (PD-L2)has been detected in various cancers. However, its prognostic value in digestive system cancers (DSCs) remains unclear. Accordingly, this meta-analysis investigated the prognostic and clinicopathological utility of PD-L2 in patients with DSCs. MethodsWe systematically searched PubMed, EMBASE, Web of Science, ClinicalTrials.gov., Scopus, and Cochrane Library databases for eligible studies up to April 30, 2020. The hazard ratio (HR), odds ratio (OR), and corresponding 95% confidence interval (CI) of the outcomes were calculated. ResultsTwenty two studies with 4886 patients were included in this meta-analysis. The pooled results showed that PD-L2 overexpression was significantly associated with poor overall survival (OS) (HR 1.470, 95% CI: 1.252–1.728, p < 0.001) and worse disease-free survival (DFS) (HR1.598, 95% CI: 1.398–1.826, p < 0.001). Subgroup analysis revealed that elevated PD-L2 was a significant prognostic indicator of worse OS in hepatocellular carcinoma (HR 1.703, 95% CI: 1.456–1.991, p < 0.001) and colorectal cancer (HR 3.811, 95% CI: 1.718–8.454, p = 0.001). Concerning clinicopathologic factors, PD-L2 overexpression was associated with lymphatic metastasis (OR 1.394., 95% CI: 1.101–1.764, p = 0.006), tumor metastasis (OR 1.599, 95% CI: 1.072–2.383, p = 0.021), and the histopathological stage (OR 0.704, 95% CI: 0.566–0.875, p = 0.002). ConclusionPD-L2 overexpression in DSCs after surgery might predict a poor prognosis, especially in hepatocellular carcinoma and colorectal cancer. Larger patient cohorts are needed to validate its prognostic role.