STAT5A and chronic myelogenous leukemia, BCR-ABL1 positive: Although HIF proteins are mainly activated by hypoxia, several reports indicated that expression and/or activity of HIF‐1α/HIF‐2α are also regulated by STAT3 (Signal Transducer and Activator of Transcription 3) and STAT5 in normal and cancer cell types including CML LSCs.19, 20, 21