CASP6 and glioblastoma: Additionally, GBM resistance to apoptosis can be due to the over-expression of inhibitors of apoptosis (Bcl-2, BIRC1, and BCL2L2) and the suppression of apoptosis inducers (BOK, PMAIP1, caspase-6, caspase-7, caspase-8, APAF1) [9].