PD-L1 expression is an independent predictor of favorable outcome in patients with localized esophageal adenocarcinoma

ABSTRACTBackground. The outcome of patients with adenocarcinoma of the esophagogastric junction (AEG) remains poor. The programmed cell-death-protein-1 (PD-1), a co-inhibitory receptor primarily expressed by T-cells, represents a potential new therapeutic target. PD-1, PD-1 ligand 1 (PD-L1), and PD-L2 expression have all been described as prognostic factors in a variety of cancers. Their expression patterns in AEG, however, are poorly understood. We analyzed PD-L1, PD-L2 and PD-1 expression by tumor-infiltrating lymphocytes (TILs) and cancer-cells in tumor-biospecimens in AEG-patients.Methods. 168 patients who underwent esophagectomy because of AEG between 1992–2011 were included in this study. PD-L1, PD-L2 and PD-1 expression were evaluated by immunohistochemistry and correlated with various clinicopathological parameters, disease-free survival (DFS) and long-term overall survival (OS).Results. PD-L1 expression by cancer-cells (cancer-cell-PD-L1+) was found in 43.5% of patients whereas PD-L1 expression b...