PIK3CB and chronic myelogenous leukemia, BCR-ABL1 positive: PPP2R5E encodes the serine/threonine protein phosphatase-2A regulatory subunit epsilon isoform involved in the PI3K/Akt, MAPK, and Ras signaling pathways and in the regulation of cancers, including chronic myelogenous leukemia (Perrotti and Neviani, 2013).