IDH1 and central nervous system cancer: The T2/FLAIR-mismatch sign was detected in 12/113 cases with lower-grade glioma (10.6%), all of them were IDH-mutant (Figure 1), 1p/19q non-codeleted tumors (6 cases with diffuse astrocytoma, IDH mutant [WHO °II] and 6 cases with anaplastic astrocytoma, IDH-mutant) and in 0/295 cases with glioblastoma (0.0%) (Table 1).