ANXA5 and chronic myelogenous leukemia, BCR-ABL1 positive: To investigate whether the increased sub-G0 population in response to bortezomib treatment in CML cells was a resultant of induction of apoptosis, K562, and AR230 cells were treated with 10, 25 and 50 nm bortezomib for 24 h and apoptosis was measured by annexin-V-FITC/PI dual staining.