We investigated by immunohistochemistry the clinical significance and the evolution of Oligodendrocyte lineage transcription factor 2 (OLIG2) and cyclin D2 (CCND2) protein expression, two markers highly specific of glioma stem cells, on a cohort of human paired glioblastoma samples comparing initial resections with recurrent tumors after radiation therapy alone or radio‐chemotherapy with temozolomide according to the Stupp regimen. This evidence concerns the gene CCND2 and central nervous system cancer.