TP53 and cancer: Indeed, the ability of Qu to exert antiproliferative and proapoptotic effects on normal cells only at very high concentrations sharply contrasts with the low concentrations needed to exert the same effects on cancer cells that are, for example, 3.5 μM for the B16-BL6 murine melanoma cell line [143], 25 μM for PC-3 (p53-null cells) and DU-145 (p53-mutated cells) human prostate cancer cell lines [116] and 10 μM for SK-Br3, MDA-MB-453 and MDA-MB-231 human breast carcinoma cells [114].