The phosphoSTAT5 — miR-21 — PDCD4 pathway was active in CML primary CD34+ cells, but also in acute myeloid leukemia (AML) models like MV4.11 and MOLM13, where the constitutively active tyrosine kinase FLT3-ITD plays a similar role to BCR-ABL1 in the K562 cell line. This evidence concerns the gene PDCD4 and chronic myelogenous leukemia, BCR-ABL1 positive.