A p53‐deficient cell line showed decreased TP53INP1 expression due to activated p73 transcriptional activity.14, 18 The transcription factor E2F1 increases TP53INP1 expression during cell cycle progression.33 TP53INP1 exerts antitumour effects through a p53‐independent pathway in breast cancer. This evidence concerns the gene E2F1 and breast cancer.