CTL and NK cells were observed by fluorescence microscopy (n = 3). 10 d after treatment, mice spleens were harvested, NK and CTL cells were elected by flow cytometry. Hepatic cancer cells carried the green fluorescent protein (GFP)-expressing vector, and upon injury by CTL and NK cells, the carrying GFP gene vectors is released from the cells in hepatic cancer tissues. GFP-expressing NK and CTL cells were observed by scanning with a fluorescence microscope (× 200 magnification). The right panel represents the phase contrast images of transfected CTL and NK cells that expressed the GFP-fluorescent marker.