Among them, oligodendrocyte lineage transcription factor 2 (OLIG2) appears as the most specific and cyclin D2 (CCND2) as the only one related to cell cycle regulation.12 The purpose of this work was to investigate by immunohistochemistry (IHC) the clinical significance and the evolution of OLIG2 and CCND2 protein expression on a cohort of human paired GBM samples comparing initial resections with recurrent tumors after radiation therapy (RT) alone or radio‐chemotherapy with temozolomide (RT‐TMZ) according to the Stupp regimen.3 Here, CCND2 is linked to glioblastoma.