Figure 2: PDT induces significant apoptosis of A549 cells. Flow cytometry results of apoptotic assays after photoirradiation with or without Ad5/F35-APE1 siRNA recombinant adenovirus, untreated group as negative control. The axis is for FITC staining and the axis is for PE staining in all graphs represented. The cells undergoing early apoptosis are FITC positive and PE-A negative in the lower right quadrants.