Moreover, there were fewer IFN-γ+ granzyme B+ antigen-specific CD8+ T cells from the tumours of Grail−/−Il21−/− mice compared to Grail−/− mice (Fig. 4h), supporting the role of IL-21R signalling in Grail−/− CD8+ T-cell expansion and function. This evidence concerns the gene CD8A and neoplasm.