FOXM1 and ovarian cancer: Interestingly, the MEK inhibitor U0126 decreased FOXM1 protein levels in OVCA433, which is an ovarian cancer cell line with functional p53, but not in SKOV3, a p53-deleted ovarian cancer cell line; this suggests that functional p53 may be necessary for the MAPK/ERK pathway to regulate FOXM1 activity [206].