In this study, the numbers of CD8+ TIICs and PD-1+ TIICs were comparable with those reported in a previous study that examined multiple cancer types, including ESCC.24 As CD8+ lymphocytes are activated and trafficked to the tumour from the tumour-draining lymph node via antigen-presenting cells reacting to tumour-associated antigens,25 the comparable numbers of CD8+ TIICs among the three locations indicate that the immune system of the host responded similarly regardless of the location in the primary tumour. This evidence concerns the gene CD8A and neoplasm.