PTPA and acute lymphoblastic leukemia: Interestingly, in bone marrow xenografts, PADs nearly abrogated survival of leukemic progenitors and dramatically impaired survival and self-renewal of CML and Ph1+ B-ALL stem and/or progenitor cells, but not of normal quiescent HSCs, through BCR–ABL1-independent and PP2A-mediated inhibition of Jak2 and β-catenin (27, 44).