IDH-mutant gliomas, the most common type of malignant brain tumor in young adults, arise from glial progenitor cells (GPBs) found in normal brain tissue[1]. The research team analyzed samples from 70 patients and found that low levels of IDH mutations were found in the tissue around the tumor in 37.9% of patients[1]. Using spatial transcriptomics and clonal evolution analysis, scientists have confirmed that glial progenitor cells with an initial IDH mutation are the origin of these tumors[1]. In a mouse model, researchers successfully reproduced tumor development by introducing the same genetic mutation into GPB mice[3]. This study demonstrated that malignant brain tumors do not arise suddenly, but begin in normal brain tissue and develop gradually over a long period[3]. The findings expand on previous research from 2018, which showed that another type of gliomas (IDH wild-type glioblastoma) originates from neural stem cells in the subventricular zone, suggesting that different types of brain tumors have different cells of origin[3].