Hence, myeloid malignancies carrying dysregulated fusion tyrosine kinase genes (TK), including platelet-derived growth factor (PDGF-AB), fibroblast growth factor receptor 1 (FGFR1), and the PCM1-JAK2 fusion product has been recently recognized by the World Health Organization (WHO) category of myeloid neoplasms with eosinophilia and rearrangement of PDGFRA, PDGFRB, or FGFR1, or with PCM1-JAK2. The gene discussed is PCM1; the disease is Increased total eosinophil count.