Apoptosis analysis by flow cytometry. A, flow cytometric analysis of propidium iodide stained DNA of three bladder cancer cell lines following Sunitinib treatment. Cells were treated with Sunitinib for 48 h for indicated concentration. Increased sub-G1 fraction the Sunitinib -treated cells provided an estimate of apoptotic cells. B, Apoptosis detected by Annexin V-FITC/PI binding assay. Cells treated with Sunitinib for 48 h were stained with Annexin V and PI before subjected to FACS for analysis.