Since inactivation of DNA-PKcs, PLK1, PP6 or Chk2 leads to mitotic defects including misaligned chromosomes, lagging chromosomes and abnormal nuclear morphologies and cytokinesis ([23,27,30,47] and Supplementary Figure S2), these findings have relevance to understanding the mechanism of aneuploidy in cancer cells. The gene discussed is PLK1; the disease is cancer.