PPP treatment triggers apoptosis in TP53 wild type but not mutated cells. (A). Each of the cell lines was treated with 500 nM PPP for 24 hours and subjected to flow cytometry for the detection of the cells in sub-G1 and cell cycle phases. (B). The experiment was repeated three times and the percentage of sub-G1 apoptotic cells is summarized in this histogram as mean + SD. **, p < 0.01.