Cell cycle analysis. Cells were treated with 5 and 25% cactus pear extract for 2 days. Cells were stained with propidium iodide/RNase A solution for 30 min then analyzed by flow cytometry using a FACScan flow cytometer. (a.) cervical cancer cells HeLa and Me180; (b.) ovarian cancer cells SKOV3 and OVCA420 (upper), and bladder cancer cells T24 (bottom).