CASP9 and cancer: To understand the underlying mechanism of the anti-cancer effect, the expression levels of the apoptosis-related proteins, including PARP, caspase-9, and Bcl-2, were detected in the Jeko-1, Rec-1, and Z138 cells after treatment with low-dose BGB-3111 (40% of the IC50) and BTZ (40% of the IC50).