The forkhead-box (FOX) genes comprise a superfamily of at least 43 members that express proteins which are involved in transcriptional regulation and may be associated with the pathogenesis of various cancers. FOX family members are monomeric, helix-turn-helix proteins with a core DNA-binding domain of approximately 110 amino acids. FOX transcription factors play roles in determining cell fate during early development. FOXR1 (forkhead box protein R1), also known as FOXN5 (forkhead box protein N5) or DLNB13, is a 292 amino acid nuclear protein that belongs to the FOX family and contains one forkhead DNA-binding domain. Through chromosomal aberrations such as retroviral integration, gene amplification or translocation, FOXR1 may be involved the development of certain invasive carcinomas.