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Examination of PHOX2B in adult neuroendocrine neoplasms reveals relatively frequent expression in phaeochromocytomas and paragangliomas
Journal article   Open access   Peer reviewed

Examination of PHOX2B in adult neuroendocrine neoplasms reveals relatively frequent expression in phaeochromocytomas and paragangliomas

John P Lee, Yin P Hung, Thomas M O'Dorisio, James R Howe, Jason L Hornick and Andrew M Bellizzi
Histopathology, Vol.71(4), pp.503-510
10/2017
DOI: 10.1111/his.13243
PMCID: PMC5597462
PMID: 28464318
url
https://www.ncbi.nlm.nih.gov/pmc/articles/5597462View
Open Access

Abstract

Paired-like homeobox 2b (PHOX2B) is a transcription factor with expression outside of the central nervous system restricted to neurons and chromaffin cells of the autonomic nervous system. Germline mutations cause congenital central hypoventilation syndrome and predispose to neuroblastoma and Hirschsprung disease. Among paediatric small round cell tumours, PHOX2B is neuroblastoma-specific. Two studies of adult autonomic nervous system tumours (n = 62) produced conflicting results (all tumours stained in one; expression restricted to 40% of paragangliomas in the other). We examined PHOX2B expression in a large cohort of phaeochromocytomas and paragangliomas, as well as well-differentiated neuroendocrine tumours (WDNETs) and poorly differentiated neuroendocrine carcinomas (PDNECs). Tissue microarrays (TMAs) were constructed from 609 tumours: 111 phaeochromocytomas, 146 paragangliomas, 250 WDNETs, and 102 PDNECs. PHOX2B immunohistochemistry was scored for extent (%) and intensity (0-3+), and an H-score (extent × intensity) was calculated. PHOX2B expression was seen in 32% of phaeochromocytomas and in 47% of paragangliomas. Mean/median H-scores for these tumours were in the 30-55 range (i.e. weak to moderate staining). No WDNETs and only 7% of PDNECs stained, the latter often strongly. In a representative cohort of corresponding whole sections (n = 55), the results in WDNETs and PDNECs were unchanged, whereas half of the phaeochromocytomas/paragangliomas that were negative on TMAs became focally, weakly positive. We found frequent, weak to moderate PHOX2B expression in phaeochromocytomas/paragangliomas and no expression in WDNETs, which could be diagnostically useful in the distinction of these tumours. Expression in a minority of PDNECs probably reflects the transcription factor lineage infidelity that is characteristic of this tumour class.
Neuroendocrine Tumors - pathology Pheochromocytoma - metabolism Paraganglioma - pathology Neuroendocrine Tumors - metabolism Tissue Array Analysis Homeodomain Proteins - metabolism Humans Transcription Factors - genetics Homeodomain Proteins - genetics Transcription Factors - metabolism Paraganglioma - metabolism Adrenal Gland Neoplasms - metabolism Pheochromocytoma - pathology Adult Neuroblastoma - metabolism Adrenal Gland Neoplasms - pathology Neuroblastoma - pathology Cohort Studies

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