The shared and diverse phenotypic characteristics of chronic MPNs have been attributed to dysregulated signal transduction, a consequence of acquired disease-causing oncogenic mutations, BCR-ABL in CML, JAK2 V617F in Ph− MPNs, and several less common oncogenes found in these diseases [26]. This evidence concerns the gene JAK2 and chronic myelogenous leukemia, BCR-ABL1 positive.