Immunohistochemical expression analysis of Olig2 and Ccnd2 was carried out on a cohort of human paired GBM samples comparing initial resections with local recurrent tumors after radiation therapy (RT) alone or radio-chemotherapy with temozolomide (RT-TMZ).
Three out of four cases showed focal amplification of the CCND2 gene or gain of the region on 12p that included CCND2, suggesting that this may be a favorable prognostic factor in GBM.
PDGFRA amplification was more common in cases with GBM than with PNET morphology (36 vs. 5 %, respectively), while CCND2 amplifications showed the opposite trend (5 vs. 27 %).