A potential role for Ape1 in promoting resistance to adjuvant therapy in primary brain tumors in addition to GBMs is supported by our findings that suppressing Ape1 expression and Ap endo activity increases the sensitivity of pediatric ependymoma cells to radiation (Bobola et al., 2011) and medulloblastoma cells to TMZ and BCNU (Bobola et al., 2005). This evidence concerns the gene APEX1 and ependymoma.