PTPA and neoplasm: Protein phosphatase 2A (PP2A) is the major cellular Ser/Thr protein phosphatase that regulates multiple cellular processes, including metabolism, DNA repair, proliferation, cell motility, apoptosis, and autophagy.4, 5, 6, 7, 8, 9 Moreover, PP2A is known to be involved in tumorigenesis.10, 11, 12, 13 Early studies identified PP2A as a tumor suppressor, but recent studies supported an oncogenic function of PP2A.