Prognostic Impact of TERT Promoter Mutations in Adult-Type Diffuse Gliomas Based on WHO2021 Criteria.

Simple Summary: Telomerase reverse transcriptase promoter (TERTp) mutation is commonly observed in brain tumors and are known to contribute to the acquisition of immortality in tumors via maintaining telomere length. In this study, we aimed to investigate the prognostic impact of several known prognostic factors, including TERTp mutations, in 528 adult-type diffuse gliomas classified according to the 2021 WHO criteria. Our data showed that TERTp mutation status had a significant impact on prognosis in the combined group of glioblastoma, IDH-wildtype and astrocytoma, IDH-mutant, but was not a predictor of prognosis within any individual tumor groups. We also showed that several known clinicopathologic factors have different prognostic significance depending on the type of tumor. This supports the need for systematic tumor diagnosis based on molecular pathology classification and indicates that multiple factors, not just TERTp mutation status, should be considered in the prognosis of tumors. Mutation in the telomerase reverse transcriptase promoter (TERTp)is commonly observed in various malignancies, such as central nervous system (CNS) tumors, malignant melanoma, bladder cancer, and thyroid carcinoma. These mutations are recognized as significant poor prognostic factors for these tumors. In this investigation, a total of 528 cases of adult-type diffuse gliomas diagnosed at a single institution were reclassified according to the 2021 WHO classifications of CNS tumors, 5th edition (WHO2021). The study analyzed clinicopathological and genetic features, including TERTp mutations in each tumor. The impact of known prognostic factors on patient outcomes was analyzed through Kaplan–Meier survival and Cox regression analysis. TERTp mutations were predominantly identified in 94.1% of oligodendrogliomas (ODG), followed by 66.3% in glioblastoma, IDH-wildtype (GBM-IDHwt), and 9.2% of astrocytomas, IDH-mutant (A-IDHm). When considering A-IDHm and GBM as astrocytic tumors (Group 1) and ODGs (Group 2), TERTp mutations emerged as a significant adverse prognostic factor (p = 0.013) in Group 1. However, within each GBM-IDHwt and A-IDHm, the presence of TERTp mutations did not significantly impact patient prognosis (p = 0.215 and 0.268, respectively). Due to the high frequency of TERTp mutations in Group 2 (ODG) and their consistent prolonged survival, a statistical analysis to evaluate their impact on overall survival was deemed impractical. When considering MGMTp status, the combined TERTp-mutated and MGMTp-unmethylated group exhibited the worst prognosis in OS (p = 0.018) and PFS (p = 0.034) of GBM. This study confirmed that the classification of tumors according to the WHO2021 criteria effectively reflected prognosis. Both uni- and multivariate analyses in GBM, age, MGMTp methylation, and CDKN2A/B homozygous deletion were statistically significant prognostic factors while in univariate analysis in A-IDHm, grade 4, the Ki-67 index and MYCN amplifications were statistically significant prognostic factors. This study suggests that it is important to classify and manage tumors based on their genetic characteristics in adult-type diffuse gliomas. [ABSTRACT FROM AUTHOR]