Sulindac induced apoptosis in colorectal (A) and lung cancer cells (B), did not induce apoptosis in breast cancer cells (C). The cells were treated with 1.6mM sulindac for 0, 8, 24 and 48 h. The DMSO was used as control. Cells were fixed with 80% ethanol for 8 h at 4 °C, then stained with propidium iodide buffer (50 μg/ml propidium iodide, 0.1% sodium citrate, and 0.1% Triton X-100) for 3 h at 4 °C. Apoptosis was analyzed using a Becton Dickinson FACScan. Columns: average from three independent experiments; bars, standard deviation. (* P < 0.01 in the comparison with control).