We found that the dual effect of the high vs. low doses of etoposide applies also to other myeloid leukemia cells such as KG1, THP-1 and HL-60, which display rapid, caffeine-independent, caspase-dependent apoptosis upon 50 uM etoposide treatment, and caffeine-sensitive caspase-3-independent apoptosis and caffeine-dependent increased granularity at 0.5 uM (data not shown). This evidence concerns the gene CASP3 and myeloid leukemia.