Since TTFields (in addition to and independent of their anti-mitotic effects) have been shown to impair DNA damage repair and promote accumulation of DNA double strand breaks in non-small cell lung cancer (NSCLC) and pleural mesothelioma cell lines [28, 29, 32], and as TMZ and CCNU are DNA alkylating agents, we next examined the effect of these modalities on DNA damage and repair in GBM cells. This evidence concerns the gene CCNO and glioblastoma.