In the TRAP cohort study of 83 oesophageal adenocarcinoma biopsies, the HER2-positive tumours were enriched for epithelial markers (EPCAM, E-cadherin), but exhibited lower immune cell infiltration (CD8+ T-cells, NK cells) and reduced expression of immune exhaustion markers (PDCD1LG2, CTLA4). Here, PDCD1LG2 is linked to neoplasm.