1. Loss of methylthioadenosine phosphorylase immunoreactivity correlates with poor prognosis and elevated uptake of 11 C-methionine in IDH-mutant astrocytoma.
- Author
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Yamamura T, Tamura K, Kobayashi D, Inaji M, Toyama Y, Wakimoto H, Kiyokawa J, Hara S, Tanaka Y, Nariai T, Shimizu K, Ishii K, and Maehara T
- Subjects
- Humans, Female, Male, Middle Aged, Prognosis, Adult, Aged, Positron-Emission Tomography, Carbon Radioisotopes, Biomarkers, Tumor metabolism, Biomarkers, Tumor genetics, Young Adult, Purine-Nucleoside Phosphorylase metabolism, Purine-Nucleoside Phosphorylase genetics, Astrocytoma genetics, Astrocytoma metabolism, Astrocytoma diagnostic imaging, Astrocytoma pathology, Astrocytoma mortality, Methionine metabolism, Brain Neoplasms genetics, Brain Neoplasms metabolism, Brain Neoplasms diagnostic imaging, Brain Neoplasms pathology, Brain Neoplasms mortality, Isocitrate Dehydrogenase genetics, Isocitrate Dehydrogenase metabolism, Mutation
- Abstract
Purpose: The proximate localization of MTAP, which encodes methylthioadenosine phosphorylase, and CDKN2A/B on Chromosome 9q21 has allowed the loss of MTAP expression as a surrogate for homozygous deletion of CDKN2A/B. This study aimed to determine whether MTAP status correlates with clinical outcomes and
11 C-methionine uptake in astrocytomas with IDH mutations., Methods: We conducted immunohistochemistry for MTAP in 30 patients with astrocytoma, IDH-mutant who underwent11 C-methionine positron emission tomography scans prior to surgical resection. The tumor-to-normal (T/N) ratio of11 C-methionine uptake was calculated using the mean standardized uptake value (SUV) for tumor and normal brain tissues. Cox regression analysis was used for multivariate survival analysis., Results: Among IDH-mutant astrocytomas, 26.7% (8/30) exhibited the loss of cytoplasmic MTAP expression, whereas 73.3% (22/30) tumors retained MTAP expression. The median progression-free survival (PFS) was significantly shorter in patients with MTAP loss than those with MTAP retention (1.88 years vs. 6.80 years, p = 0.003). The median overall survival (OS) was also shorter in patients with MTAP loss than in MTAP-retaining counterparts (5.23 years vs. 10.69 years, p = 0.019). Multivariate analysis identified MTAP status (hazard ratio (HR), 0.081) and extent of resection (HR, 0.104) as independent prognostic factors for PFS. Astrocytomas lacking cytoplasmic MTAP expression showed a significantly higher median T/N ratio for11 C-methionine uptake than tumors retaining MTAP (2.12 vs. 1.65, p = 0.012)., Conclusion: Our study revealed that the loss of MTAP expression correlates with poor prognosis and an elevated T/N ratio of11 C-methionine uptake in astrocytoma, IDH-mutant., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)- Published
- 2024
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