Figure 4. Confocal imaging of cancer cells infected with A1-R, expressing GFP, in vivo. Bacterial colonies were detected in both stem-like (A) and non-stem (D) tumors. Frozen section microscopy showed infiltrating A1-R in both spindle-shaped stem-like (B and C) and round non-stem cells (E and F). (C and F) are high magnification images of (B and E), respectively. Scale bars, 20 μm.