CDKN2A and oligodendroglioma: For IDH-mutant, 1p19q-codeleted oligodendrogliomas, CDKN2A/B HD was not seen in Grade 2 tumors and was associated with poorer prognosis only in Grade 3 tumors according to a major study.9 Our results show that ALT is enigmatically seen in a proportion of both Grades 2 and 3 oligodendrogliomas in spite of the presence of TERTp mutations, and is associated with a worse prognosis (Supplementary Table 6).