ID1 and cancer: Using two model systems with a combined transcriptomic analysis and large scare siRNA screen, we demonstrated the important role of the Id proteins in the cell cycle process, which is corrupted in a cancer context by Id targets such as Kif11 and Aurka. This has importantly led to the identification of the Kif11 small molecule inhibitor ispinesib to eradicate the Id1+ cells that are resistant to paclitaxel.