Indeed, although both SUMO1 and SUMO2 have been identified to be expressed in glioma stem cells (Fig. 2B) [44, 45], and since human glioblastoma cells reflect a return to a foetal/embryonic developmental cell state [46], SUMO2 being indispensable to the development but not in adult physiology is plausibly a more potential target in anti-GBM therapeutics than SUMO1 in targeting glioblastoma stem cells. Here, SUMO1 is linked to glioblastoma.