MYC and breast cancer: Since MEK1/2 inhibitors target CEP55 through MYC (Fig 5B) and increased sensitivity of CEP55 knockdown cells to anti‐mitotic agents, we tested whether CEP55 overexpressing breast cancer cells can be targeted by combination of a selective MEK1/2 inhibitor (AZD6244) and the anti‐mitotic drug (PLK1 inhibitor, BI2535).