Since previous studies have shown that decreased phosphorylation of the PP2Ac subunit at Y307 is correlated with increased PP2A activity [18] and that decreased phosphorylation of c-MYC at serine 62 reduces c-MYC stability [10, 11], we investigated whether phosphorylation of these proteins is reduced in T-ALL cell lines upon treatment with OP449. Here, PTPA is linked to acute lymphoblastic leukemia.