Clinical significance of the 2016 WHO classification in Japanese patients with gliomas

In this study, we retrospectively compared the prognostic value of the 2016 WHO classification with the former classification in 387 patients with glioma treated at our institution. According to the new classification, diagnoses included oligodendroglioma withisocitrate dehydrogenase (IDH) mutation and 1p/19q co-deletion (5.4%), anaplastic oligodendroglioma withIDH mutation and 1p/19q co-deletion (3.4%), diffuse astrocytomaIDH-mutated (3.9%), anaplastic astrocytomaIDH-mutated (2.8%), glioblastomaIDH-mutated (7.8%), glioblastomaIDH-wildtype (58.4%), diffuse midline gliomaH3 K27M mutation (2.6%), oligodendroglioma NOS (1.3%), anaplastic oligodendroglioma NOS (0.8%), diffuse astrocytomaIDH-wildtype (2.8%), and anaplastic astrocytomaIDH-wildtype (10.9%). The prognoses ofIDH-mutated astrocytomas clearly varied according to tumor grade. However, we identified no survival difference betweenIDH-wildtype anaplastic astrocytomas and glioblastomas; additionally, these tumors showed similar gene expression profiles. After exclusion of those without 1p/19q co-deletion, patients with oligodendroglial tumors showed excellent survival regardless of tumor grade. Our evaluation of chromosomal aberrations suggests that the MAPK/PI3K pathway plays a role in acquired malignancy of astrocytic tumors, whereasTP53 participates in tumorigenesis. We suspect the RB pathway also plays a role in tumorigenesis ofIDH-mutated gliomas. The new WHO classification more clearly reflects the tumorigenesis of gli...
Source: Brain Tumor Pathology - Category: Neurology Source Type: research