Elderly patients with diff use gliomas are increasing in number and their prognoses are potentially poor. Clinicians are often reluctant to off er aggressive treatments in a real-world setting. Genetic, epigenetic, and expression analyses have refi ned the traditional, histopathology-based diagnosis of diff use gliomas. The purpose of this review is to glance at clinical and pathological aspects of diffuse gliomas in the elderly. In addition, for better understanding of current state of “elderly glioma” practice, we conducted a multi-institutional cohort study and analyzed characteristics and outcomes of elderly cases enrolled in Kansai Molecular Diagnosis Network for CNS Tumors.

5-aminolevulinic acid (5-ALA) is a natural biochemical precursor of heme, which is converted by the heme synthesis pathway into protoporphyrin IX (PpIX) in mitochondria. Under the administration of 5-ALA, cancer cells, such as malignant glioma cells, cannot convert PpIX into heme at the final step of the heme biosynthesis pathway, and consequently, PpIX accumulates within mitochondria. PpIX has photosensitive characteristics, and thus, leads to the visualization of cancer cells that accumulate PpIX. Fluorescence-guided resection using 5-ALA for malignant gliomas can improve the resection rate of lesions during surgery because of the visualization of highly invasive gliomas. Recent studies have demonstrated that 5-ALA also interacts with ultrasound, hyperthermia and ionizing irradiation in cancer. In this article, we review the literature and discuss a role of 5-ALA for glioma therapy, in particular, malignant gliomas, with personal opinions.

Pilocytic astrocytoma (PA) is a WHO grade I tumor that is histologically characterized by a mixture of compact bipolar cells and loose textured astrocytes. PA has been classified into the other astrocytic tumors which is a different category from diffuse astrocytic and oligodendroglial tumors in the recent revised WHO 2016 classification.PA frequently occurs in cerebellum, as well as the supratentorial hemispheric and optico-hypothalamic regions. Recent molecular analysis demonstrated that gene expression profiles of the tumor differ among these three regions. BRAF tandem duplication resulting in the K1AA1549-BRAF fusion gene is the most frequent genetic alteration in PA. The BRAF V600E mutation is less frequently detected than the K1AA1549-BRAF fusion. More recently, it has been recommended that pilocytic astrocytoma with anaplasia should be designated as anaplastic astrocytoma with piloid features according to the results of methylation-based classifications. Clinical trials involving molecular targeted therapies using MAPK pathway inhibitors are ongoing and several promising results have been reported. Clinically, some PAs show spontaneous regression, while other PAs demonstrate spinal dissemination without the evidence of histological malignant transformation. The biological mechanism of these unusual clinical features will be dissected using molecular techniques in the near future.