The Clinicopathological Significance and Prognostic Value of PD-L2 in Patients with HCC, ICC and PAAD: A Meta-Analysis

Abstract

<strong>Background:</strong> Programmed cell death ligand 2 (PD-L2) is overexpressed in several tumors, and is associated with cancer progression and patient prognosis. Our study was aimed to investigate the clinical and prognostic significance of PD-L2 in hepatocellular carcinoma, cholangiocarcinoma and pancreatic cancer via meta-analysis. <strong>Methods: </strong>The PubMed, EMBASE, Google Scholar were searched till March 4, 2021 for relevant literature published in English. The articles selected based on the pre-defined criteria were further screened and evaluated. Hazard ratio (HR) and 95% confidence interval (95% CI) are used to evaluate the effect of PD-L2 level on overall survival (OS) and disease-free survival (DFS). The relationship between PD-L2 and pathological characteristics was evaluated in terms of the odds ratio (OR). Publication bias was checked. <strong>Results:</strong> Eight studies published from 2007 to 2019 were selected for the meta-analysis including 1725 patients. Our results indicated the high level of PD-L2 correlated positively with shorter OS (HR = 1.77, 95% CI: 1.48–2.10, P &lt; 0.00001) and worse DFS (HR = 1.86, 95% CI: 1.40–2.48, P &lt; 0.0001).PD-L2 level was positively correlated with larger tumors (OR = 1.96, 95% CI: 1.22–3.15, P = 0.005) and worse Barcelona (BCLC) stage (0–A and B–C groups, HR = 0.56, 95% CI: 0.34–0.94, p = 0.03), but not with other factors. No obvious publication bias was detected. <strong>Conclusion: </strong>PD-L2 overexpression may predict worse OS and DFS in hepatocellular carcinoma, cholangiocarcinoma and pancreatic cancer, and is correlated to tumor size and BCLC stage.