Fig. 4.

FZD8 is required for tumor growth in vivo. a Representative pictures of PC-3-derived tumors implanted on the CAM for 3 days. Left, overview image of the egg; right, representative tumors from PC-3 cells transfected with control (siCtrl) and FZD8 siRNAs. Implantation area is confined by a plastic ring; scale bars ~5 mm. b Average tumor size, as determined by ImageJ, relative to control tumors. Error bars indicate SD from three independent experiments, each with 12–15 eggs per condition (*p < 0.05 by Student's t-test). c Boxplot of tumor size in a representative experiment with 12–15 eggs per condition (**p < 0.001 by Student's t-test). d Relative FZD8 mRNA levels were determined by q-RT-PCR at day 0, when cells were implanted on the CAM and at the endpoint, when CAM tumors were excised from the egg. Error bars indicate SD of three independent experiments (*p < 0.05, **p < 0.001 by Student's t-test). e Immunohistochemical staining of CAM tumors. Representative images of sections immunostained for FZD₈ and vimentin in control (siCtrl) and FZD8-silenced (siFZD8) CAM tumors; arrows show chick embryo cells, which can be distinguished from PC-3 cells by the absence of vimentin staining, scale bar 50 µm