RAR-related orphan receptor gamma (RORγ) is a protein that in humans is encoded by the RORC (RAR-related orphan receptor C) gene. RORγ is a member of the nuclear receptor family of transcription factors. It is mainly expressed in immune cells (Th17 cells) and it also regulates circadian rhythms. It may be involved in the progression of certain types of cancer. Two isoforms are produced from the same RORC gene, probably by selection of alternative promoters. RORγ (also referred to as RORγ1) – produced from an mRNA containing exons 1 to 11. RORγt (also known as RORγ2) – produced from an mRNA identical to that of RORγ, except that the two 5'-most exons are replaced by an alternative exon, located downstream in the gene. This causes a different, shorter N-terminus.