HOXB1 is a sequence-specific transcription factor that functions as a developmental regulator providing cells with positional identities along the anterior-posterior body axis 1. As a homeodomain-containing protein, HOXB1 binds DNA regulatory regions containing TAATTA palindromic sites to activate transcription of target genes including Otx2 2. During embryogenesis, HOXB1 expression in the hindbrain is dynamically regulated through reciprocal repression with Egr2, establishing sharp segmental boundaries through coupling with retinoic acid signaling 3. HOXB1 cooperates with HOXA1 to specify rhombomere identities; double mutants exhibit severe hindbrain remodeling and craniofacial defects including loss of rhombomeres 4-5 and branchial arch tissues 4. Beyond developmental roles, HOXB1 functions as a tumor suppressor in glioma, where reduced expression correlates with malignancy and worse survival; miR-3175 directly suppresses HOXB1 to promote glioblastoma cell proliferation and invasion 5. Retinoic acid regulates spermiogenesis through HOXB1 and Sonic hedgehog signaling in testicular germ cells 6. Autosomal recessive HOXB1 mutations cause sensorineural hearing loss through defective efferent olivocochlear motor neuron development affecting outer hair cell survival 7. While HOXA1/HOXB1 variants showed no significant association with autism spectrum disorder in meta-analysis 8, the gene remains clinically relevant for hereditary congenital facial paresis.