CASP9 and breast cancer: With regard to the fact that caspase 9 is also one of the proteins of the intrinsic pathway of the apoptotic process [13,15], we analyzed its activity in breast cancer cells (MCF-7 and MDA-MB-231) under the impact of the tested seleno-organic compounds (EDAG-1 and EDAG-8) and cisplatin following a 24 h exposure to them (concentrations of 0.5 and 1 μM).