fixed in 70% ethanol for overnight at 4°C, treated with RNase-A (10 ug/mL; Sigma-Aldrich, USA), and stained with propidium iodide (50 μg/mL; Sigma-Aldrich, USA) for 30 min at room temperature in the dark and analyzed in a FACS Calibur flow cytometer and Cell Quest software (BD...