E2F1 and breast carcinoma: Transcriptional activation of E2F1 (promotes cell growth)Coactivator regulationEnhances tumor progression and metastasisEnhances self-association of SOX2Allows MLL1/2 recruitment during stem cell divisionRegulates retinoid acid-mediated RARβ2 gene activationAllows coupling of transcription and mRNA splicingFacilitates the expression of select RNAsSensitizes human breast cancers to chemotherapy drugs