Imatinib turned out to block PDGF receptor at low dose, exerting a pharmacological effect for BCR-ABL positive CML and FIP1L1-PDGFRA mutated eosinophilic leukemia patients [51, 52], suggesting PDGF signaling as an activated effector in hematological malignancies. Here, FIP1L1 is linked to Chronic Eosinophilic Leukemia, Not Otherwise Specified.