In normoxia (21% O2) and hypoxia (1% O2), treatment with the MDM2 inhibitors, nutlin- 3a and navtemadlin, reduced cell growth in the three p53 wildtype (p53WT) cell lines (human colorectal carcinoma HCT116 p53+/+; human breast carcinoma MCF7; mouse melanoma B16-F10 p53+/+) (Fig. 1a–c). This evidence concerns the gene MDM2 and breast carcinoma.