We defined p53 null/mutant cancers from the TCGA breast cancer dataset as those with a deep deletion of TP53 concomitant with very low TP53 mRNA expression, or having a deleterious mutation of TP53. CCNE2 was significantly higher in p53 null/mutant breast cancers with genome doubling than in those with a near-diploid genome. This evidence concerns the gene TP53 and cancer.