Secondly, SFN upregulates ROS production, induces mitochondrial oxidative damage, mitochondrial membrane potential depolarization, cytochrome c release, and induces an imbalance between Bax and Bcl-2; downregulates the proteins of inhibitor of apoptosis proteins (IAP) family members, activates caspase-9, caspase −3, and cleavage of PARP; upregulates glucose-regulated protein (GRP) 78 and C/EBP-homologous protein (CHOP) expression; and accumulation of p-Nrf2 in the nucleus; thereby induces apoptosis in BC cells. This evidence concerns the gene CASP9 and breast cancer.