Phox2b Immunohistochemical Staining in Detecting Enteric Neural Crest Cells in Hirschsprung Disease

Abstract

Background It can be challenging to recognize undifferentiated/immature ganglion cells, especially single forms. Ganglion cells and glia are derived from enteric neural crest cells (ENCCs), a group of autonomic nervous system (ANS)-lineage neural crest progenitors that PHOX2B regulates. Phox2b is an excellent marker for neoplastic and non-neoplastic ANS cells (eg, peripheral neuroblastic tumors [pNTs]). We hypothesized that Phox2b immunohistochemical staining (IHC) would also be useful for detecting ENCCs. Methods Hematoxylin and eosin, calretinin IHC, and Phox2b IHC were reviewed on 21 pull-through specimens and on a cohort of 12 rectal biopsies. Results Phox2b IHC demonstrated nuclear positivity in all of the ganglion cells across the different phases of differentiation without background staining. The Phox2b result correlated with the morphological findings, calretinin IHC results, and diagnoses based on the routine diagnostic method. The intensity was uniformly strong in the undifferentiated/immature forms and became variable in the mature forms; this pattern was similar to that seen in pNTs. Conclusion Phox2b IHC was highly sensitive and specific for detecting ganglion cells. It worked especially well for immature ganglion cells, seen in premature neonates, and scattered single forms in transition zones. In basic research settings, Phox2b can be a useful marker for early differentiation of ENCCs.

Spectrum of paired‐like homeobox 2b immunoexpression in pediatric brain tumors with embryonal morphology

“…In normal development, the PHOX2B gene is a key transcription factor important for neural crest development and differentiation to sympathetic neurons 5 . PHOX2B is expressed in the early human embryo in the terminal rhombomeres 4‐8 in the hindbrain of the CNS and in many neural crest derivatives like sympathetic chain ganglia, the 7th, 9th and 10th ganglionic complexes, 14 and neuro‐enteric ganglia in both neuronal and glial precursors 15 . PHOX2B polyalanin expansion and frameshift mutations have been linked to CNS disease (i.e., congenital central hypoventilation syndrome) with neural crest‐derived tumors (neuroblastoma) and neural crest migration defects (Hirschsprung disease) 14 …”

“…5 PHOX2B is expressed in the early human embryo in the terminal rhombomeres 4-8 in the hindbrain of the CNS and in many neural crest derivatives like sympathetic chain ganglia, the 7th, 9th and 10th ganglionic complexes, 14 and neuro-enteric ganglia in both neuronal and glial precursors. 15 PHOX2B polyalanin expansion and frameshift mutations have been linked to CNS disease (i.e., congenital central hypoventilation syndrome) with neural crest-derived tumors (neuroblastoma) and neural crest migration defects (Hirschsprung disease). 14 Diffuse expression of PHOX2B is a characteristic feature of peripheral neuroblastoma, and its expression is reduced with more cellular differentiation, a feature that was observed in cases 31 (post-treatment) and 34 (ganglioneuroblastoma).…”