E2F1 and breast cancer: To further investigate the mechanism underlying the promotion of tumor growth by ANP32E, we restored E2F1 in ANP32E‐inhibited cells (SUM159PT and BT‐549) and inhibited E2F1 in ANP32E‐overexpressing human breast cancer cells (SUM159PT and MDA‐MB‐361) to verify the mechanistic linkage between ANP32E, E2F1, and cyclin E (CCNE) in mediating cell proliferation.