PD-1 expression is typically higher on memory CD8+ T cells than naive counterparts and as adoptively transferred tumour-specific Tcm-phenotype CD8+ T cells, in keeping with established trafficking patterns for Tcm [26] and Tcm-like cells [27], likely first encounter DC presenting tumour antigens in lymphoid tissues, where differentiation to effectors may occur we set out to examine this. The gene discussed is CD8A; the disease is neoplasm.