To provide insights into the inherent role of PP2A inactivation in promoting immune cell infiltration in CRC, we first demonstrated that mouse intestinal tumours, developed by the conditional deletion of Ppp2r1a (gene encoding PP2A scaffold protein in 95%) in Lgr5+ crypt stem cells (referred to as Ppp2r1a−/−)21, increased infiltration of CD8+ T cells and CD20+ B cells but decreased FOXP3+ regulatory T cell (Treg) infiltration (Fig. 1a) and enriched cytokine, chemokine, interferon (IFN)-γ, and JAK-STAT pathways (Fig. 1b). Here, CD8A is linked to colorectal carcinoma.