Consistently, both FOXM1 and KIF20A have been shown to be upregulated by mitotic inhibitors at the post-translational levels.18, 20, 21 In agreement, KIF20A levels were also detected at lower levels in FoxM1−/− MEFs compared with WT MEFs (Figure 2d) as well as in MDA-MB-231 breast cancer cells after FOXM1 depletion (Supplementary Figure S3). Here, FOXM1 is linked to breast cancer.