T-cell–inflamed gene expression profile (GEP) and PD-L1 expression in patients (pts) with esophageal cancer (EC).

26Background: GEP and PD-L1 expression have been associated with anti–PD-1/PD-L1 therapy. In this retrospective observational study we explored the prognostic value of GEP and PD-L1 expression in pts with EC receiving standard-of-care therapy (SOC). Methods: Tumor tissue samples collected from 2005 to 2017 were procured from Yonsei Cancer Center (South Korea), Memorial Sloan Kettering Cancer Center (USA) and Aarhus University Hospital (Denmark). GEP score was derived from an 18-gene signature using extracted tumor RNA analyzed by NanoString nCounter; GEP high/intermediate (GEP-H/I) and low were defined by a cutoff of –1.540, consistent with pembrolizumab clinical trials. PD-L1 expression was assessed by PD-L1 IHC 22C3 pharmDx assay (Agilent); positive was defined as combined positive score (CPS) ≥ 10, where CPS is the the number of PD-L1–positive cells (tumor cells, lymphocytes and macrophages) divided by the total number of viable tumor cells, multiplied by 100. Associations of GEP score and PD-L1 expres...