Retinoic acid receptor beta (RAR-beta), also known as NR1B2 (nuclear receptor subfamily 1, group B, member 2) is a nuclear receptor that in humans is encoded by the RARB gene. This gene encodes retinoic acid receptor beta, a member of the thyroid-steroid hormone receptor superfamily of nuclear transcriptional regulators. This receptor localizes to the cytoplasm and to subnuclear compartments. It binds retinoic acid, the biologically active form of vitamin A which mediates cellular signalling in embryonic morphogenesis, cell growth and differentiation. It is thought that this protein limits growth of many cell types by regulating gene expression. The gene was first identified in a hepatocellular carcinoma where it flanks a hepatitis B virus integration site. A deregulation of this gene has also been detected in uterine cervical carcinoma preneoplastic lesions. The gene expresses at least two transcript variants; one additional transcript has been described, but its full length nature has not been determined.