Survival of TP53 mutant medulloblastoma (UW228) cells after the combination treatment with 2 mM lithium and radiation. A) Survival curves for TP53 mutant cells given increasing radiation doses following 24 hours exposure to lithium (red) and untreated control (blue) (p < 0.01). B) Increase in luciferase activity in treated cells (red) over control (blue) in TP53 mutant cells (p < 0.01). C) Immunofluorescent imaging of the nuclear translocation of β-catenin (bottom panel); β-catenin (green), nucleus (DAPI-red), co-localization (yellow) following 24 hours exposure to lithium. D) γH2AX foci in non-irradiated cells and 24 hours post irradiation: γH2AX foci (green), nucleus (blue).