IDH1 and neoplasm: Indeed, in a study of 218 aHGGs where a similar percentage (64%) were IGF-1R positive compared with 75% here, IGF-1R did associate with adverse outcome.5 The discrepancy between these data and ours could relate to differences in proportion of stage III and IV disease, and/or unbalanced frequency of IDH mutation, which was not stated in ref.,5 while we found a trend to increased IDH1 mutation frequency in the IGF-1R moderate/strong vs negative/weak tumours (19.5% vs 12.5%, p = 0.12).