The importance of loss of PP2A activity for CML disease progression is also supported by the ability of PP2A to induce Rb dephosphorylation (Avni et al, 2003) and suppress Jak2 kinase, which was found activated in CML-BC (Xie et al, 2002). The gene discussed is PTPA; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.