E2F1 and breast carcinoma: SND1 has been identified as a transcriptional co‐activator of several transcription factors.[22] In particular, previous studies have demonstrated that SND1 could promote the transcriptional activity of E2F1 and facilitate the transcriptional activation of E2F1 target genes, which play crucial roles in G1/S transition.[24] In this regard, we confirmed the interaction between SND1 and E2F1 in breast cancer cells using a co‐immunoprecipitation (co‐IP) assay (Figure7A,B).