Table 1: Current classification of the NR superfamily into subfamilies according to sequence homology. Trivial abbreviations are given in brackets. NRs implicated in head and neck tumorigenesis are given in bold; asterisks indicate orphan receptors.

SubfamilyFull nameSubfamily members (trivial abbreviation)

Subfamily 1Thyroid hormone receptor-like receptors

SubgroupsPeroxisome proliferator-activated receptorsPeroxisome proliferator-activated receptor (PPAR)
Retinoic acid receptorsRetinoic acid receptor (RAR)
Retinoic acid receptor-related orphan receptorsRetinoic acid receptor-related orphan receptor (ROR)
Rev-ErbA Rev-ErbA (EAR1)
Thyroid hormone receptorsThyroid hormone receptor (TR)
Liver X receptor-like receptors Liver X receptor (LXR) ; Farnesoid X receptor (FXR)
Vitamin D receptor-like receptorsVitamin D receptor (VDR); Pregnane X receptor (PXR); Constitutive androstane receptor (CAR)

Subfamily 2Retinoid X receptor-like receptors

SubgroupsHepatocyte nuclear factor-4Hepatocyte nuclear factor-4 (HNF-4)
Retinoid X receptorsRetinoid X receptor (RXR)
Testicular receptors Testicular receptor 2, 4 (TR2/4)
Tailless-like receptors Human homologue of the Drosophila tailless gene (TLX); Photoreceptor cell-specific nuclear receptor (PNR)
Chicken ovalbumin upstream promoter-transcription factor-like receptors Chicken ovalbumin upstream promoter-transcription factor (COUP-TF) I, II; V-erbA-related (EAR2)

Subfamily 3Estrogen receptor-like receptors

SubgroupsEstrogen receptorsEstrogen receptor (ER)
Estrogen related receptors Estrogen-related receptor (ERR)
3-Ketosteroid receptorsAndrogen receptor (AR); Progesterone receptor (PR);Glucocorticoid receptor (GR); Mineralocorticoid receptor (MR);

Subfamily 4Nerve growth factor IB-like receptors

Nerve Growth factor IB/ Nuclear receptor related/ Neuron-derived orphan receptor Nerve Growth factor IB (NGF-IB); Nuclear receptor related 1 (NURR1); Neuron-derived orphan receptor 1 (NOR1)

Subfamily 5Steroidogenic factor-like receptors

Steroidogenic factor/Liver receptor homolog Steroidogenic factor 1 (SF1); Liver receptor homologue-1 (LHR1)

Subfamily 6Germ cell nuclear factor-like receptors

Germ cell nuclear factor Germ cell nuclear factor (GCNF)

Subfamily 0Miscellaneous receptors

Dosage-sensitive sex reversal, adrenal hypoplasia critical region/Small heterodimer partner Dosage-sensitive sex reversal, adrenal hypoplasia critical region, on chromosome X, gene 1 (DAX); Small heterodimer partner (SHP)