CASP9 and glioblastoma: In apoptotic processes, the conversion to cleavage (active) caspase 3 and caspase 9 leads to a decrease of procaspase 3 and procaspase 9 expression levels.27 Active caspase 3 and caspase 9 expression levels becoming a determinant for apoptotic pathways were analyzed in human DBTRG glioblastoma cells at 2, 12, 24 and 48 h (Figure 5) in our study.