In chronic myelogenous leukemia (CML) and B-cell leukemias, miR-21 is upregulated in response to radiation and influences downstream targets such as PTEN, vascular endothelial growth factor (VEGF), and hypoxia-inducible factor-1α (HIF1-α)[72]. This evidence concerns the gene VEGFA and chronic myelogenous leukemia, BCR-ABL1 positive.