PPM1D and leukemia: To test the relative sensitivity of leukemia cells with Ppm1d activation to cytotoxic therapies, we mixed Ppm1dT476∗-fl/+ leukemia cells with Ppm1d+/+ leukemia cells, and cultured the cells for 10 days in the presence of dimethyl sulfoxide, Cisplatin, GSK2830371 (a PPM1D inhibitor), or Cisplatin with GSK2830371 (supplemental Figure 4A).16