Liver cancer cells were seeded at a density of 3×105 cells/well into 6-well plates and cultured for 24 h. Subsequently, cells were transfected with control siRNA or an siRNA targeting human STEAP1, and incubated for 72 h. After incubation, floating cells in media were collected and adhesive cells were washed, fixed in ethanol, and stained with propidium iodide using a cell-cycle analysis kit (FxCycle PI/RNase Staining Solution; Thermo Fisher Scientific), followed by analysis on a BD FACS II (BD Biosciences) instrument using FACSDiva (BD Biosciences) as previously described (20 (link)).