BCR and chronic myelogenous leukemia, BCR-ABL1 positive: BCR/ABL regulates hnRNP E2 expression depending on enhanced phosphorylation of hnRNP E2 by BCR/ABL-activated MAPKERK1/2, and high level of BCR/ABL is essential to maintain BCR/ABL-MAPKERK1/2-hnRNP-E2-C/EBPα differentiation inhibitory pathway in CML myeloid progenitor cells [117] (Figure 5).