CASP8 and glioblastoma: Silencing of CASP8 gene by hypermethylation of CASP8 promoter CGIs resulted in complete absence of its protein expression, which may explain the absence of apoptotic elimination of the cells with genomic damage and the uncontrolled cell growth; therefore, hypermethylation of CASP8 promoter CGIs has been considered as a common hallmark of relapsed glioblastoma multiforme [18].