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The IDH-wild-type lower-grade astrocytomas are a heterogeneous entity. According to 2021 WHO classification, IDH-wild-type astrocytomas with any of the following factors show poor prognosis: combination of chromosome 7 gain and 10 loss (+7/-10), and/or EGFR amplification, and/or TERT promoter (TERTp) mutation. Multiplex ligation-dependent probe amplification (MLPA) can detect copy number alterations with a reasonable cost. The purpose of this study was to find precise and cost-effective method for stratifying the prognosis of IDH-wild-type astrocytomas. Sanger sequencing, MLPA, and quantitative methylation-specific PCR were performed for 42 IDH-wild-type lower-grade astrocytomas surgically treated at Kyoto University Hospital, and overall survival was analyzed for 40 patients. Of the 42 IDH-wild-type astrocytomas, 21 were classified as grade 4 in 2021 WHO classification and all of them had either TERTp mutation or EGFR amplification. Kaplan-Meier analysis confirmed the prognostic significance of 2021 WHO Classification, and WHO grade was also prognostic. Cox regression hazard model identified PTEN loss and PDGFRA amplification as independent significant prognostic indicators (Risk ratio of 9.75, p< 0.001 and 13.9, p=0.002). The classification recommended by 2021 WHO Classification could be completed using Sanger sequencing and MLPA. Survival analysis revealed PTEN and PDGFRA were significant prognostic factors for IDH-wild-type lower-grade astrocytomas.

Molecular diagnosis in brain tumors has been widely spread after the publication of WHO 2016 classification. But it become a major problem that there are some tumors not to be classified on its criteria, especially in pediatric neuroepithelial tumors. To clarify the characteristics of gliomas in pediatric and adolescent and young adult age (AYA), we picked up 131 neuroepithelial tumors under 30-year-old at Kyoto University and analyze their molecular profiles. Hot spot mutations in IDH1/2, H3F3A, HIST1H3B, TERT promoter, and BRAF were analyzed by Sanger sequencing, and 1p/19q codeletion was examined by FISH or MLPA. With the pathohistological diagnosis and genetic information, all tumors were classified based on WHO 2016 classification. The terms “not otherwise specified” (NOS) and “not elsewhere classified” (NEC) were used based on cIMPACT-NOW. There were 25 glioblastomas and 34 pilocytic astrocytomas, which accounted for a larger percentage than in adult tumors. IDH-wild type gliomas accounted for 55% in diffuse astrocytomas and 69% in anaplastic astrocytomas. The percentages of gliomas with NEC were 50% of oligodendrogliomas and 20% in anaplastic oligodendrogliomas, respectively. Most pilocytic astrocytomas were under 20-year-old (27 patients) and located in infratentorial area (21 patients). Based on WHO 2016 classification, not a few neuroepithelial tumors in pediatric and AYA ages could be classified clearly. These tumors had more different genetic abnormalities than those in adult. Therefore, it may be important to evaluate these tumors with comprehensive genetic analysis.

OBJECTIVE Diffuse astrocytomas are classified as WHO grade II and its median overall survival (mOS) is 10 to 11 years. The efficacy of chemoradiation in the high-risk feature has been reported. The prognosis is associated with IDH and TERT promoter (TERTp) mutations. Here, we retrospectively analyzed the patients with diffuse astrocytoma treated with vincristine, ACNU, carboplatin and interferon-β plus radiotherapy (VAC-feron-R)in our institute. PATIENTS AND METHODS Between December 2003 to January 2016, 44 patients were diagnosed as diffuse astrocytoma with integrated diagnosis of histological and molecular analysis. The average age was 43.1 years (22–71 years). They received VAC-feron-R as initial treatment in our institute. We analyzed the IDH1/2 and the TERTp mutation using Sangar sequencing and determined the 1p/19q codeletion by the fluorescence in situ hybridization or the multiplex ligation-dependent probe amplification. RESULTS Median follow-up period was 76.5 months, mPFS was 126 months, mOS did not reach, and 10-year survival rate was 60%.IDH status was determined in 29 patients, 9 mutant and 20 wild types. There was no significant difference in PFS and OS between the two groups. TERTp status was determined in 18 patients with IDH wild type, 6 mutant and 12 wild types. mPFS of patients with TERTp wild type did not reach, but that with TERTp mutant type was 34.5 months (p = 0.0356). CONCLUSION Compared with previous clinical studies, VAC-feron-R showed a favorable clinical outcome in diffuse astrocytoma. The impact of TERTp status on prognosis was identified but not IDH status in this cohort.