PP2A is a crucial tumor suppressor and suppresses the tumorigenic characteristics of cells including disordered cell proliferation and stemness, by suppressing various tumor-promoting signals such as c-Myc, Akt/PKB, ERK1/2, mTORC1/p70 S6 kinase (p70S6K), Wnt/β-catenin, and NFκB8–10. The gene discussed is MAPK3; the disease is neoplasm.