Abstract
BACKGROUND AND PURPOSE: In the WHO 2021 classification, glioblastoma is limited to IDH-wildtype and is diagnosed when microvascular proliferation and necrosis are present. Furthermore, even in the presence of morphologically low-grade findings, the diagnosis of glioblastoma is made if there is either EGFR gene amplification, TERT promoter mutation, or +7/-10 chromosome copy number alterations. Therefore, we investigated IDH wild-type lower-grade astrocytoma. CASES: 10 patients were included in this study. Sanger sequencing was performed for TERT promoter mutations, and MLPA was further implemented using probes for EGFR and PTEN genes in TERT wild-type cases. The threshold values for copy number change were homozygous deletion (x≤0.4), loss of heterozygosity (LOH) (0.4