Fig. 6.

TG2 is expressed exclusively in N-Myc-negative neuroblastoma cells and is up-regulated by an HDAC inhibitor in vivo. (a) Neuroblastoma tissue sections from N-Myc transgenic mice were double-labeled with an anti-N-Myc antibody, which was visualized by using DAB (brown, in the nucleus), and an anti-TG2 antibody, which was visualized by using AEC (red in the cytoplasm, indicated with arrowheads). The nucleus was counterstained with haematoxylin (blue). (b) Neuroblastoma-bearing N-Myc transgenic mice were treated with control or 20 mg per kilogram of body weight of TSA for 1 week before euthanizing. Tumor volume was measured. Error bars indicate standard error. (c) Formalin-fixed tissue sections from the mice were subjected to immunohistochemical assessment of TG2 protein expression, which was visualized by using DAB. The nucleus was counterstained with haematoxylin. Arrows indicate positive cytoplasmic TG2 staining in tumor cells. (Scale bar, 10 μm.)