Publication:

A single-centre observational study of 124 surgically managed glioma patients: molecular subtyping and its correlation with clinico-radiological profile

Background The World Health Organization (WHO) 2016 classification incorporated molecular subtyping in glioma, highlighting the diagnostic and prognostic significance. The study aims to determine the isocitrate dehydrogenase (IDH-1) gene, α-thalassemia/mental retardation syndrome X-linked (ATRX) gene, and tumor suppressor gene-53 (p53) mutation in glioma and their correlation with various clinical and radiological parameters.

Methods In this prospective observational study, histopathological slides of glioma (2017-2018), were analyzed for IDH-1, ATRX and p53 mutations and their correlation with various clinical and radiological parameters.

Results IDH-1 mutation was found in 48 (38.7%), ATRX loss in 38 (30.6%) and p53 mutation in 40 (32.5%) patients. The expression of IDH-1 was significantly higher (43.7%) in adults; however, no significant difference was seen with gender. Also 51.2% of patients, who presented with seizures, showed IDH-1 expression; and 27.7% of patients, who had neurological deficit also showed IDH-1 expression. IDH-1 expression was high in glioma located at insula (73.3%) and parietal lobe (71.4%); while ATRX loss was seen in glioma located at insula (80%). Intraventricular glioma characteristically lacks all three markers: IDH-1 expression, p53 overexpression and ATRX loss. IDH-1 expression and p53 overexpression was seen mainly in diffuse fibrillary astrocytoma, oligodendroglioma, anaplastic astrocytoma and glioblastoma.

Conclusions Molecular subtyping is of paramount importance in glioma management. IDH-1 mutation is commonly observed in adults and patients presenting with seizures. The duration of symptoms correlates with IDH-1 and ATRX mutations. Hypothalamic tumors lack all three mutations.