reported that over 30% of primary GBMs change their subtypes upon recurrence,[31] and this cellular plasticity is common in GBM with wild‐type IDH.[14] A recent study confirmed this idea[26] by barcoding a specific subtype before orthotopic implantation in mice followed by single cell RNA sequencing (RNAseq) and barcode analysis of different GBM state in the same tumor. Here, IDH1 is linked to glioblastoma.