FOXH1 is a forkhead box transcription factor that functions as a key mediator of TGF-β/activin signaling during early development 1. It recognizes specific DNA sequences and forms transcriptionally active complexes with SMAD2/SMAD4 proteins on target gene promoters 1. FOXH1 is expressed primarily during early embryonic stages and serves as a primitive-streak specifier 2. Mechanistically, FOXH1 exhibits context-dependent regulatory functions. It acts as a transcriptional activator in developmental pathways, particularly in mediating TGF-β superfamily signals 1. However, FOXH1 also functions as a repressor of flk1 (VEGF receptor) transcription, negatively regulating vascular formation in zebrafish 3. FOXH1 expression is regulated by NANOG and LIN28 during cellular reprogramming and requires H3K79 demethylation 2. In liver progenitor cells, FOXH1-SMAD complexes are essential for HNF4α expression, which controls coagulation factor production during acute liver failure 4. Clinically, FOXH1 mutations cause developmental disorders including holoprosencephaly, heterotaxy, and 3C syndrome 5. Recent evidence suggests FOXH1 involvement in hepatocellular carcinoma progression, where upregulation via TCF12 promotes cell proliferation 6. FOXH1 is essential for human pluripotent stem cell fitness and proper reprogramming 7. Dysregulation of FOXH1 expression affects multiple developmental and disease processes.