Two different ways for CML cells to adapt to hypoxia were also evidenced: a “rapid adaptation” (occurring within 1 day of incubation in hypoxia) of cell bulk emerged, capable to prevent BZ-induced caspase activation, apoptosis and BCR/Ablprotein suppression, and the consequent destruction of culture. The gene discussed is BCR; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.