 HL-60 cell model was used to study the effect of DNA topoisomerase (topo) IIα and IIβ on differentiation and apoptosis of cells and is especially useful in dielectrophoresis studies, which require an aqueous environment with suspended and round cells.Furthermore, these cells have been used in order to investigate whether intracellular calcium plays a role in caspase activation induced by reactive oxygen species.Chromatin and gene expression profiling in HL-60 cells and differentiated cells derived from these has been performed recently.