However, for IDH-wild-type lower-grade astrocytoma, some papers have stated that PTEN loss is associated with poor prognosis27,32, potentially because PTEN is a tumour suppressor gene27,33 and inactivation of PTEN signalling is thus important to malignant progression to glioblastoma34. Here, IDH1 is linked to astrocytoma (excluding glioblastoma).