Analysis of NOX4 expression in different glioma subtypes using the Gliovis data portal for visualisation [44] revealed differences between tumour and non‐tumour cells, with highest expression of NOX4 recorded in GBM and in grade IV tumours compared with low‐grade glioma tumours (Fig. 1C, Fig. S1b) in two different datasets: the Repository for Molecular Brain Neoplasia Data (REMBRANDT) [45] and the Gravendeel dataset [46]. The gene discussed is NOX4; the disease is glioma.