PTPA and acute myeloid leukemia: For example, Smith et al. observed low PP2A activity in leukemic blasts from AML patients, and pharmacological activation of PP2A can enhance the cytotoxicity of fms-like tyrosine kinase 3 (FLT3) tyrosine kinase inhibitors (TKIs) in FLT3+ AML cells via targeting extracellular-regulated protein kinase (ERK) and Akt [22].