title: Diagnostic utility of PHOX2B in primary and treated neuroblastoma and in neuroblastoma metastatic to the bone marrow.
abstract: BACKGROUND
  Neuroblastoma (NB) is the most common extracranial tumor of childhood. Although most cases have a distinctive histology, a subset of primitive cases require immunohistochemical studies to distinguish them from other small round blue cell tumors of childhood. Immunohistochemistry is also used to detect small amounts of tumor metastatic to the bone marrow and in posttreatment samples with obscuring fibrosis, calcification, or inflammation. The transcription factor PHOX2B is essential for the differentiation and survival of sympathetic neurons and chromaffin cells, and therefore is highly specific for the peripheral autonomic nervous system.
  
  
  OBJECTIVE
  To determine the diagnostic utility of PHOX2B immunohistochemistry as a marker of primary, treated, and metastatic NB.
  
  
  METHODS
  Neuroblastoma tissue microarrays were stained with PHOX2B, CD57, and synaptophysin. Arrays containing rhabdomyosarcoma, Ewing sarcoma, and Wilms tumor were stained with PHOX2B, and negative bone marrow samples were stained with PHOX2B and CD57.
  
  
  RESULTS
  PHOX2B and CD57 were similar to synaptophysin in their ability to detect NB. PHOX2B and CD57 similarly showed robust staining in posttreatment NB and NB metastatic to the bone marrow. In contrast to the cytoplasmic staining pattern seen with synaptophysin and CD57, clear and strong nuclear PHOX2B permitted identification of individual tumor cells. PHOX2B staining was absent in all cases of rhabdomyosarcoma, Ewing sarcoma, and Wilms tumor, and in the negative bone marrow.
  
  
  CONCLUSIONS
  PHOX2B and CD57 are useful markers of NB. PHOX2B is specific for NB in its differential diagnosis with other small round cell tumors, and its nuclear staining may be helpful for accurate bone marrow tumor quantification.
authors.affiliation: From the Departments of Pathology, Microbiology and Immunology (Drs Hata, Correa, Black, and Mobley), Pediatrics (Dr Esbenshade), and Pediatric Surgery (Dr Chung), Vanderbilt University Medical Center, Nashville, Tennessee; and the Department of Pathology, Dell Children's Medical Center, Austin, Texas (Dr Krishnan).
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Hata
authors.forename: Hernan
authors.initials: H
authors.lastname: Correa
authors.forename: Chandra
authors.initials: C
authors.lastname: Krishnan
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Esbenshade
authors.forename: Jennifer O
authors.initials: JO
authors.lastname: Black
authors.forename: Dai H
authors.initials: DH
authors.lastname: Chung
authors.forename: Bret C
authors.initials: BC
authors.lastname: Mobley
mesh_terms: D019046:Bone Marrow Neoplasms / Q000378:metabolism* / Q000556:secondary; D018959:CD57 Antigens / Q000096:biosynthesis; D003937:Diagnosis, Differential; D018398:Homeodomain Proteins / Q000096:biosynthesis*; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D009447:Neuroblastoma / Q000175:diagnosis / Q000378:metabolism* / Q000601:surgery; D015203:Reproducibility of Results; D012208:Rhabdomyosarcoma / Q000175:diagnosis / Q000378:metabolism; D012512:Sarcoma, Ewing / Q000175:diagnosis / Q000378:metabolism; D012680:Sensitivity and Specificity; D016708:Synaptophysin / Q000096:biosynthesis; D046888:Tissue Array Analysis; D014157:Transcription Factors / Q000096:biosynthesis*; D009396:Wilms Tumor / Q000175:diagnosis / Q000378:metabolism
chemical_list: D018959:CD57 Antigens; D018398:Homeodomain Proteins; C109220:NBPhox protein; D016708:Synaptophysin; D014157:Transcription Factors