PDGFRB and Increased total eosinophil count: Another important example of the integration of molecular aberrations in the 2008 WHO classification of hematological malignancies is the newly introduced group of myeloid and lymphoid neoplasms with eosinophilia and abnormalities of PDGFRA, PDGFRB, or FGFR1. This reclassification highlights the consideration of the targetable alterations FIP1L1-PDGFRA or PDGFRB-rearrangements and those harboring FGFR1-rearrangements, indicating response or resistance to Imatinib [2,16].