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- Bengtsson, Daniel, 1975-, et al.
(författare)
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Long-Term Outcome and MGMT as a Predictive Marker in 24 Patients With Atypical Pituitary Adenomas and Pituitary Carcinomas Given Treatment With Temozolomide
- 2015
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Ingår i: Journal of Clinical Endocrinology & Metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 100:4, s. 1689-1698
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Tidskriftsartikel (refereegranskat)abstract
- Context/Objective: Locally aggressive pituitary tumors (LAPT) and pituitary carcinomas respond poorly to conventional therapy and cytotoxic drugs. Temozolomide (TMZ) is an oral alkylating drug with good tolerability, approved for treatment of malignant gliomas. The experience of its use in pituitary tumors is limited. Design and Setting: We report on 24 patients with aggressive pituitary tumors (16 LAPTs, 8 carcinomas) treated with TMZ for a median of 6 months (range 1-23). Follow-up ranged from 4 to 91 months with a median of 32.5 months. 19/24 tumors were hormone secreting (PRL 9, ACTH 4, GH 4, GH/PRL 2). Ki-67 was 2-50% in LAPTs, and 5-80% in carcinomas. Main Outcome: Response to TMZ and the association with tumor expression of O6-methylguanine DNA methyltransferase (MGMT), MLH1, MSH2, and MSH6, examined by immunohistochemistry. Results: Complete tumor regression occurred in two carcinomas and persisted at follow-up after 48 and 91 months, respectively. Partial regress of tumor mass ranging from 35% to 80% occurred in 5 LAPTs and 2 carcinomas. Another patient with LAPT had a 71% decrease in prolactin levels without change in tumor volume. Three LAPTs could not be evaluated. Median MGMT staining was 9% (5-20%) in responders vs 93% (50-100%) in nonresponders. Loss of MSH2 and MSH 6 was observed in a single patient who had a rapid development of resistance to TMZ. Conclusions: This study shows that TMZ is a valuable treatment option for patients with uncontrolled pituitary tumors. The data suggest that tumoral MGMT staining below 50% is associated with a high likelihood of treatment response.
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| 3. |
- 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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