Murine double minute 2 (MDM2), a key downregulator of TP53, is overexpressed in patients’ CD34+ cells, and treatment with idasanutlin, a second-generation inhibitor of TP53-MDM2 interaction, has been shown to target MPN stem and progenitor cells both alone and in combination with IFNα [144]. This evidence concerns the gene TP53 and myeloproliferative disorder.