IDH1 and glioma: If we look to our toolbox, multiple options are available for this task: immunohistochemistry for IDH1 R132H can be used to exclude the most frequent (about 90% of supratentorial IDH-mutant gliomas) mutation and this strategy has been found to be adequate for patients aged 55 and older since the probability of finding an alternative mutation in this setting is less than 1% [38].