PTPA and breast cancer: Among these, expression and/or activity of the PP2A targets Myc, STAT5, MAPK, Akt, BAD and Rb (Neviani et al, 2005, and references therein) are either essential for BCR/ABL leukaemogenesis or have been found altered in CML-BC (Calabretta and Perrotti, 2004, and references therein).