IDH1 and astrocytoma (excluding glioblastoma): In order to find out what molecular mechanism may be behind the different ability to perform the mesenchymal transformation of OPC-like cells obtained from diffuse gliomas of different grades, we decided to compare OPC-like cells isolated by using flow cytometry-based sorting from astrocytoma, IDH-mut, grade 3 and grade 4, as well as oligodendrogliomas, IDH-mut, grade 3, with their analogs isolated from the same neoplasms that had grade 2.