Analysis of IDH1-R132 mutation, BRAF V600 mutation and KIAA1549-BRAF fusion transcript status in central nervous system tumors supports pediatric tumor classification.

Objective: Gliomas are the leading cause of cancer-related morbidity in children and comprise a clinical, histological and molecular heterogenous group of CNS tumors. Appropriate treatment of these tumors relies on correct classification into tumor types and malignancy grades.

Methods: We examined 170 (0-18 years) pediatric and 131 (19-35 years) young adult brain tumors including pilocytic astrocytomas (PAs), pilomyxoid astrocytomas (PMAs), diffuse astrocytomas (DAs), gangliogliomas, dysembryoplastic neuroepithelial tumors (DNTs) and pleomorphic xanthoastrocytomas (PXAs) for IDH1 and BRAF mutation/BRAF fusion gene status.

WT1 expression increases with malignancy and indicates unfavourable outcome in astrocytoma.

Aims: The zinc finger transcription factor WT1 is expressed in astrocytic neoplasms and therefore is a potential target of immunotherapy in brain tumours. Our aim was to further elucidate the role of WT1 as a diagnostic and prognostic marker in neuropathology, particularly as to the differentiation of astrocytoma from oligodendroglioma as well as to the dependency of WT1 expression on clinically relevant parameters.

Methods: 829 evaluable brain tumour samples were investigated by WT1 immunohistochemistry on full tissue routine slides, consisting of 442 glioblastomas, 303 astrocytomas, 41 oligodendrogliomas and 43 oligoastrocytomas.