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AliasesPHOX2B, NBLST2, NBPhox, PMX2B, paired like homeobox 2b, CCHS
External IDsOMIM: 603851 MGI: 1100882 HomoloGene: 68371 GeneCards: PHOX2B
Gene location (Human)
Chromosome 4 (human)
Chr.Chromosome 4 (human)[1]
Chromosome 4 (human)
Genomic location for PHOX2B
Genomic location for PHOX2B
Band4p13Start41,744,082 bp[1]
End41,748,970 bp[1]
RefSeq (mRNA)



RefSeq (protein)



Location (UCSC)Chr 4: 41.74 – 41.75 MbChr 5: 67.09 – 67.1 Mb
PubMed search[3][4]
View/Edit HumanView/Edit Mouse

Paired-like homeobox 2b (PHOX2B), also known as neuroblastoma Phox (NBPhox), is a protein that in humans is encoded by the PHOX2B gene located on chromosome 4.[5]

It codes for a homeodomain transcription factor. It is expressed exclusively in the nervous system, in most neurons that control the viscera (cardiovascular, digestive and respiratory systems). It is also required for their differentiation.


Essential for the differentiation and survival of sympathetic neurons and chromaffin cells, the transcription factor PHOX2B is highly specific for the peripheral autonomic nervous system. Neuroblasts are derived from sympathoadrenal lineage neural crest cells and therefore require and constitutively express PHOX2B. PHOX2B immunohistochemical staining, as a marker of neural crest derivation, has been shown to be sensitive and specific for undifferentiated neuroblastoma, enabling identification where other markers fail to recognize neuroblastoma among various different small round blue cell tumors of childhood.[6][7][8][9]

The diagnostic utility of PHOX2B staining extends to later stages of differentiation. Its strength and specificity can detect the small foci of neuroblastic tumors metastatic to the bone marrow, an identification critical for determining disease staging. PHOX2B staining also overcomes frequent obstacles to neuroblastoma detection in post-treatment samples, which frequently exhibit dense fibrosis, prominent inflammatory infiltrates, and/or diffuse calcification.[10]


Mutations in human PHOX2B cause a rare disease of the visceral nervous system (dysautonomia): congenital central hypoventilation syndrome (associated with respiratory arrests during sleep and, occasionally, wakefulness), Hirschsprung's disease (partial agenesis of the enteric nervous system), ROHHAD, and tumours of the sympathetic ganglia. In most people, Exon 3 of the gene contains a sequence of 20 polyalanine repeats. An increase in the number of repeats is associated with congenital central hypoventilation syndrome. There may also be other pathogenic mutations further along the gene.


  1. ^ a b c GRCh38: Ensembl release 89: ENSG00000109132 - Ensembl, May 2017
  2. ^ a b c GRCm38: Ensembl release 89: ENSMUSG00000012520 - Ensembl, May 2017
  3. ^ "Human PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  4. ^ "Mouse PubMed Reference:". National Center for Biotechnology Information, U.S. National Library of Medicine.
  5. ^ "Entrez Gene: paired-like homeobox 2b".
  6. ^ Bielle, Franck; Fréneaux, Paul; Jeanne-Pasquier, Corinne; Maran-Gonzalez, Aurélie; Rousseau, Audrey; Lamant, Laurence; Paris, Régine; Pierron, Gaëlle; Nicolas, André Victor; Sastre-Garau, Xavier; Delattre, Olivier; Bourdeaut, Franck; Peuchmaur, Michel (2012). "PHOX2B Immunolabeling". The American Journal of Surgical Pathology. 36 (8): 1141–1149. doi:10.1097/PAS.0b013e31825a6895. PMID 22790854.
  7. ^ Hata, Jessica L.; Correa, Hernan; Krishnan, Chandra; Esbenshade, Adam J.; Black, Jennifer O.; Chung, Dai H.; Mobley, Bret C. (2015). "Diagnostic Utility of PHOX2B in Primary and Treated Neuroblastoma and in Neuroblastoma Metastatic to the Bone Marrow". Archives of Pathology & Laboratory Medicine. 139 (4): 543–546. doi:10.5858/arpa.2014-0255-OA. PMID 25822764.
  8. ^ Hung, Yin P.; Lee, John P.; Bellizzi, Andrew M.; Hornick, Jason L. (2017). "PHOX2B reliably distinguishes neuroblastoma among small round blue cell tumours". Histopathology. 71 (5): 786–794. doi:10.1111/his.13288. PMID 28640941.
  9. ^ Warren, Mikako; Matsuno, Ryosuke; Tran, Henry; Shimada, Hiroyuki (2018). "Utility of Phox2b immunohistochemical stain in neural crest tumours and non-neural crest tumours in paediatric patients". Histopathology. 72 (4): 685–696. doi:10.1111/his.13412. PMID 28986989.
  10. ^ Hata et al. (2015).

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