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Miyauchi M, Akashi T, Furukawa A, Uchida K, Tamura T, Ando N, Kirimura S, Shintaku H, Yamamoto K, Ito T, Miura K, Kayamori K, Ariizumi Y, Asakage T, Kudo A, Tanabe M, Fujii Y, Ishibashi H, Okubo K, Murakami M, Yamada T, Takemoto A, Bae Y, Eishi Y, Ohashi K. PHOX2B is a Sensitive and Specific Marker for the Histopathological Diagnosis of Pheochromocytoma and Paraganglioma. Endocr Pathol 2022; 33:506-518. [PMID: 36029394 DOI: 10.1007/s12022-022-09730-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/19/2022] [Indexed: 11/28/2022]
Abstract
Pheochromocytomas (PCCs) and paragangliomas (PGLs) are non-epithelial neuroendocrine neoplasms originating from the adrenal medulla and paraganglion of the sympathetic and parasympathetic nervous system, respectively. PCCs and PGLs show histological similarities with other epithelial neuroendocrine neoplasms and olfactory neuroblastomas (ONBs), and the differential diagnosis of PGLs is particularly difficult. Therefore, we compared the sensitivity of PHOX2A, PHOX2B, and tyrosine hydroxylase (TH) in the histopathological diagnosis of PCCs and PGLs immunohistochemically using the tissue microarrays of 297 neoplasms including PCCs, PGLs, neuroblastomas, ganglioneuromas, epithelial neuroendocrine neoplasms, and ONBs. Using cutoff values of 25%, 5%, and 5% of tumor cells expressing PHOX2A, PHOX2B, and TH, respectively, as positive, 40 of 51 PCCs, 32 of 33 parasympathetic/head and neck PGLs (HNPGLs), 17 of 19 sympathetic/thoracoabdominal PGLs (TAPGLs), and 12 of 152 epithelial neuroendocrine neoplasms, including 123 well-differentiated and 29 poorly differentiated neuroendocrine neoplasms, were PHOX2A-positive. All 51 PCCs, 33 HNPGLs, and 19 TAPGLs were PHOX2B-positive, while all 152 epithelial neuroendocrine neoplasms were PHOX2B-negative. Moreover, 50 of 51 PCCs, 13 of 33 HNPGLs, all TAPGLs, and 12 of 152 epithelial neuroendocrine neoplasms were TH-positive. All ONBs were negative for PHOX2A, PHOX2B, and TH. PHOX2B was the most sensitive and specific diagnostic marker for PCCs and PGLs among PHOX2A, PHOX2B, and TH. PHOX2B can facilitate identification of PCCs and PGLs from epithelial neuroendocrine neoplasms and ONBs, especially in the case of HNPGLs, in which TH is often negative.
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Affiliation(s)
- Minami Miyauchi
- Department of Human Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takumi Akashi
- Department of Diagnostic Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8519, Japan.
- Division of Surgical Pathology, Tokyo Medical and Dental University Hospital, Tokyo, Japan.
| | - Asuka Furukawa
- Department of Human Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Keisuke Uchida
- Department of Human Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
- Division of Surgical Pathology, Tokyo Medical and Dental University Hospital, Tokyo, Japan
| | - Tomoki Tamura
- Division of Surgical Pathology, Tokyo Medical and Dental University Hospital, Tokyo, Japan
| | - Noboru Ando
- Division of Surgical Pathology, Tokyo Medical and Dental University Hospital, Tokyo, Japan
| | - Susumu Kirimura
- Division of Surgical Pathology, Tokyo Medical and Dental University Hospital, Tokyo, Japan
| | - Hiroshi Shintaku
- Division of Surgical Pathology, Tokyo Medical and Dental University Hospital, Tokyo, Japan
| | - Kurara Yamamoto
- Department of Human Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takashi Ito
- Department of Human Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Keiko Miura
- Division of Surgical Pathology, Tokyo Medical and Dental University Hospital, Tokyo, Japan
| | - Kou Kayamori
- Department of Oral Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yosuke Ariizumi
- Department of Head and Neck Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Takahiro Asakage
- Department of Head and Neck Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Atsushi Kudo
- Department of Hepatobiliary and Pancreatic Surgery, Tokyo Medical and Dental University Hospital, Tokyo, Japan
| | - Minoru Tanabe
- Department of Hepatobiliary and Pancreatic Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yasuhisa Fujii
- Department of Thoracic Surgery, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hironori Ishibashi
- Department of Urology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kenichi Okubo
- Department of Urology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Masanori Murakami
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Tetsuya Yamada
- Department of Molecular Endocrinology and Metabolism, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Akira Takemoto
- Division of Surgical Pathology, Tokyo Medical and Dental University Hospital, Tokyo, Japan
- Bioresource Research Center, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yuan Bae
- Department of Pathology, Japanese Red Cross Medical Center, Tokyo, Japan
| | - Yoshinobu Eishi
- Department of Human Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Kenichi Ohashi
- Department of Human Pathology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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Di Lascio S, Belperio D, Benfante R, Fornasari D. Alanine Expansions Associated with Congenital Central Hypoventilation Syndrome Impair PHOX2B Homeodomain-mediated Dimerization and Nuclear Import. J Biol Chem 2016; 291:13375-93. [PMID: 27129232 PMCID: PMC4933246 DOI: 10.1074/jbc.m115.679027] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Indexed: 11/30/2022] Open
Abstract
Heterozygous mutations of the human PHOX2B gene, a key regulator of autonomic nervous system development, lead to congenital central hypoventilation syndrome (CCHS), a neurodevelopmental disorder characterized by a failure in the autonomic control of breathing. Polyalanine expansions in the 20-residues region of the C terminus of PHOX2B are the major mutations responsible for CCHS. Elongation of the alanine stretch in PHOX2B leads to a protein with altered DNA binding, transcriptional activity, and nuclear localization and the possible formation of cytoplasmic aggregates; furthermore, the findings of various studies support the idea that CCHS is not due to a pure loss of function mechanism but also involves a dominant negative effect and/or toxic gain of function for PHOX2B mutations. Because PHOX2B forms homodimers and heterodimers with its paralogue PHOX2A in vitro, we tested the hypothesis that the dominant negative effects of the mutated proteins are due to non-functional interactions with the wild-type protein or PHOX2A using a co-immunoprecipitation assay and the mammalian two-hybrid system. Our findings show that PHOX2B forms homodimers and heterodimerizes weakly with mutated proteins, exclude the direct involvement of the polyalanine tract in dimer formation, and indicate that mutated proteins retain partial ability to form heterodimers with PHOX2A. Moreover, in this study, we investigated the effects of the longest polyalanine expansions on the homeodomain-mediated nuclear import, and our data clearly show that the expanded C terminus interferes with this process. These results provide novel insights into the effects of the alanine tract expansion on PHOX2B folding and activity.
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Affiliation(s)
- Simona Di Lascio
- From the Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, 20129 Milan, Italy and
| | - Debora Belperio
- From the Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, 20129 Milan, Italy and
| | - Roberta Benfante
- From the Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, 20129 Milan, Italy and the National Research Council (CNR) Neuroscience Institute, 20129 Milan, Italy
| | - Diego Fornasari
- From the Department of Medical Biotechnology and Translational Medicine, Università degli Studi di Milano, 20129 Milan, Italy and the National Research Council (CNR) Neuroscience Institute, 20129 Milan, Italy
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Khan AO, Almutlaq M, Oystreck DT, Engle EC, Abu-Amero K, Bosley T. Retinal Dysfunction in Patients with Congenital Fibrosis of the Extraocular Muscles Type 2. Ophthalmic Genet 2014; 37:130-6. [PMID: 24940936 DOI: 10.3109/13816810.2014.926942] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Congenital fibrosis of the extraocular muscles type 2 (CFEOM2) is a distinct non-syndromic form of congenital incomitant strabismus secondary to orbital dysinnervation from recessive mutations in the gene PHOX2A. The phenotype includes bilateral ptosis, very large angle exotropia, ophthalmoplegia, and poorly-reactive pupils. Other than amblyopia, afferent visual dysfunction has not been considered part of CFEOM2; however, we have repeatedly observed non-amblyopic subnormal vision in affected patients. The purpose of this study was to document this recurrent feature of the phenotype. METHODS A retrospective case series (2002-2012). RESULTS Eighteen patients (four families) were identified; all affected individuals had confirmed homozygous recessive PHOX2A mutations except one individual for whom genetic testing was not done because of multiple genetically confirmed family members. Age at assessment ranged from 5-62 years old (median 10 years old). All patients had decreased best-corrected visual acuity not completely explainable by amblyopia in both the preferred and non-preferred eye. In those patients who had further ancillary testing, visual fields (five patients) and electroretinography (10 patients) confirmed abnormalities not ascribable to amblyopia. CONCLUSIONS In addition to a distinct form of congenital incomitant strabismus, the phenotype of CFEOM2 includes subnormal vision consistent with retinal dysfunction. This could be the direct result of PHOX2A mutations or a secondary effect of orbital dysinnervation.
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Affiliation(s)
- Arif O Khan
- a Division of Pediatric Ophthalmology , King Khaled Eye Specialist Hospital , Riyadh , Saudi Arabia
| | - Mohammed Almutlaq
- a Division of Pediatric Ophthalmology , King Khaled Eye Specialist Hospital , Riyadh , Saudi Arabia
| | - Darren T Oystreck
- b Department of Ophthalmology , College of Medicine, King Saud University , Riyadh , Saudi Arabia .,c Division of Ophthalmology, Faculty of Health Sciences , University of Stellenbosch , Tygerberg , South Africa , and
| | - Elizabeth C Engle
- d Divisions of Neurology and Ophthalmology , Children's Hospital , Boston , MA , USA
| | - Khaled Abu-Amero
- b Department of Ophthalmology , College of Medicine, King Saud University , Riyadh , Saudi Arabia
| | - Thomas Bosley
- b Department of Ophthalmology , College of Medicine, King Saud University , Riyadh , Saudi Arabia
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