Transcription factor regulating the expression of cell cycle genes essential for DNA replication and mitosis (PubMed:19160488, PubMed:20360045). Plays a role in the control of cell proliferation (PubMed:19160488). Also plays a role in DNA break repair, participating in the DNA damage checkpoint response (PubMed:17101782). Promotes transcription of PHB2 (PubMed:33754036). Interacts with PINT87aa which is encoded by the circular form of the long non-coding RNA LINC-PINT; the interaction inhibits FOXM1-mediated transcription of PHB2. Isoform 1 and isoform 2 appear to be the only activators of gene transcription. Isoform 3, found in rat, does not seem to exist in human. Expressed in thymus, testis, small intestine, colon followed by ovary. Appears to be expressed only in adult organs containing proliferating/cycling cells or in response to growth factors. Also expressed in epithelial cell lines derived from tumors. Not expressed in resting cells. Isoform 2 is highly expressed in testis. Embryonic expression pattern: liver, lung, intestine, kidney, urinary tract; adult expression pattern: intestine, colon, testis and thymus. Induced during liver regeneration and oxidative stress. Within the protein there is a domain which acts as a transcriptional activator. Insertion of a splicing sequence within it inactivates this transcriptional activity, as it is the case for isoform 4. Phosphorylated in M (mitotic) phase. Phosphorylation by the checkpoint kinase CHEK2 in response to DNA damage increases the FOXM1 protein stability probably stimulating the transcription of genes involved in DNA repair. Phosphorylated by CDK1 in late S and G2 phases, creating docking sites for the POLO box domains of PLK1. Subsequently, PLK1 binds and phosphorylates FOXM1, leading to activation of transcriptional activity and subsequent enhanced expression of key mitotic regulators.