In combination with loss of nuclear ATRX expression, IDH1, 1p/19q and TERT promoter mutations define the most frequent type of infiltrative astrocytoma [14, 15], while mutations in the EGFR gene (seen in 35 % of all cases of glioblastoma) are associated with primary glioblastoma [16]. The gene discussed is IDH1; the disease is glioblastoma.