TFPI-2 induces apoptosis in NPC cells. A: CNE2 cells were transfected with empty vector and TFPI-2, then stained with annexin V-FITC and PI and subjected to flow cytometry. Fluorescence dot blots of annexin V-positive (horizontal axis) and PI-positive (vertical axis) cells are shown. B: Cells that were positively stained by annexin V-FITC only (early apoptosis) and positive for both annexin V-FITC and PI (late apoptosis) were quantitated, and both subpopulations were considered as apoptotic cells. The bar graph shows the average in 5 experiments. Error bars show standard deviations.