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- Casar Borota, Olivera, et al.
(författare)
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Corticotroph Aggressive Pituitary Tumors and Carcinomas Frequently Harbor ATRX Mutations
- 2021
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Ingår i: Journal of Clinical Endocrinology & Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 106:4, s. 1183-1194
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Tidskriftsartikel (refereegranskat)abstract
- Context: Aggressive pituitary tumors (APTs) are characterized by unusually rapid growth and lack of response to standard treatment. About 1% to 2% develop metastases being classified as pituitary carcinomas (PCs). For unknown reasons, the corticotroph tumors are overrepresented among APTs and PCs. Mutations in the alpha thalassemia/mental retardation syndrome X-linked (ATRX) gene, regulating chromatin remodeling and telomere maintenance, have been implicated in the development of several cancer types, including neuroendocrine tumors. Objective: To study ATRX protein expression and mutational status of the ATRX gene in APTs and PCs. Design: We investigated ATRX protein expression by using immunohistochemistry in 30 APTs and 18 PCs, mostly of Pit-1 and T-Pit cell lineage. In tumors lacking ATRX immunolabeling, mutational status of the ATRX gene was explored. Results: Nine of the 48 tumors (19%) demonstrated lack of ATRX immunolabelling with a higher proportion in patients with PCs (5/18; 28%) than in those with APTs (4/30;13%). Lack of ATRX was most common in the corticotroph tumors, 7/22 (32%), versus tumors of the Pit-1 lineage, 2/24 (8%). Loss-of-function ATRX mutations were found in all 9 ATRX immunonegative cases: nonsense mutations (n = 4), frameshift deletions (n = 4), and large deletions affecting 22-28 of the 36 exons (n = 3). More than 1 ATRX gene defect was identified in 2 PCs. Conclusion: ATRX mutations occur in a subset of APTs and are more common in corticotroph tumors. The findings provide a rationale for performing ATRX immunohistochemistry to identify patients at risk of developing aggressive and potentially metastatic pituitary tumors.
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- Asa, S L, et al.
(författare)
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From pituitary adenoma to pituitary neuroendocrine tumor (PitNET) : an International Pituitary Pathology Club proposal
- 2017
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Ingår i: Endocrine-Related Cancer. - 1351-0088 .- 1479-6821. ; 24:4, s. C5-C8
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Tidskriftsartikel (refereegranskat)abstract
- The classification of neoplasms of adenohypophysial cells is misleading because of the simplistic distinction between adenoma and carcinoma, based solely on metastatic spread and the poor reproducibility and predictive value of the definition of atypical adenomas based on the detection of mitoses or expression of Ki-67 or p53. In addition, the current classification of neoplasms of the anterior pituitary does not accurately reflect the clinical spectrum of behavior. Invasion and regrowth of proliferative lesions and persistence of hormone hypersecretion cause significant morbidity and mortality. We propose a new terminology, pituitary neuroendocrine tumor (PitNET), which is consistent with that used for other neuroendocrine neoplasms and which recognizes the highly variable impact of these tumors on patients.
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- Casar-Borota, Olivera, et al.
(författare)
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A novel dynamin-2 gene mutation associated with a late-onset centronuclear myopathy with unusual clinical presentation and necklace fibres
- 2012
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Ingår i: Neuromuscular Disorders. - Oxford : Elsevier BV. - 0960-8966 .- 1873-2364. ; 22:9-10, s. 843-843
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Nuclear centralisation and internalisation, sarcoplasmic radiating strands and type 1 muscle fibre predominance and hypotrophy are morphologic features of centronuclear myopathy (CNM) related to dynamin-2 (DNM2) gene defects, whereas necklace fibres characterise late-onset myopathy associated with myotubularin-1 (MTM1) gene defects. We report a 40-year-old woman with 1-year history of pain and paresthesia in the left shoulder and arm that was clinically interpreted as brachial plexus neuritis. Electromyography revealed both myopathic and neuropathic abnormalities, and because of the myopathic changes a muscle biopsy was performed. The typical morphologic features of dynamin-2 CNM with additional numerous necklace fibres were found in the muscle biopsy. Sequencing of the DNM2 and MTM1 genes revealed a not previously described heterozygous missense mutation in exon 18 of DNM2 leading to replacement of highly conserved Proline in position 647 by Arginine. The muscle symptoms have not progressed during the two-year follow-up, but the patient has developed bilateral subtle lens opacities. Necklace fibres were originally described as fibres that had usually a small diameter and internalized nuclei aligned in a basophilic ring at a few micrometers beneath the sarcolemma. They were described in association with myopathies caused by MTM1 mutations, and similar but not identical fibres have also been reported in a case of DNM2 associated CNM. Our findings support the concept that necklace fibres are not specific but indicate common pathogenic mechanisms in DNM2 and MTM1 associated CNM. This case report expands the clinical, morphological and molecular genetic variability of DNM2 associated CNM.
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