Indeed, HIF‐2α was previously shown to be a target gene of STAT5 in CML LSCs and, in line, our data indicate that ACF inhibits the expression of both STAT5 and HIF‐2α proteins in K562 cells cultured in hypoxic conditions.20, 21. Here, STAT5B is linked to chronic myelogenous leukemia, BCR-ABL1 positive.