Expression of the p53 R248Q mutant alters the distribution of breast cancer cells xenotransplanted into zebrafish. (A) MDA-MB-231-SH, (B) -R248Q and (C) -R248Q-TA cells were pretreated with 30 ng/ml doxycycline for 48 h and injected into the common cardinal vein of transgenic Tg(fli1:EGFP) zebrafish embryos with green fluorescent vasculature. Representative images of the embryos 3 days post injection are displayed. The distribution of the cells was analyzed in the posterior 2-mm section of ≥50 embryos for each cell type (box with white outline), based on the fluorescence intensity profiles (white profiles below the boxes). Based on fluorescence intensity profiles, the position of each cell within the measurement box was calculated and the distribution of cells in subsections covering the posterior (D) 2 or (E) 0.5 mm of the embryo was analyzed. The plots present the mean relative cancer cell frequencies in these sections for the analyzed embryo populations. ****P<0.0001 and Q<0.0003. p53, tumor suppressor p53; EGFP, enhanced green fluorescent protein; SH, cells with silenced endogenous p53; TA, transactivatory domain disruption (L22S/W23Q) in addition to R248Q mutation