PGR and breast cancer: Instead, in SK-Br-3 breast cancer cells (ER−, PR−, HER2+) defective in Bak, treatment with 100 μM of kaempferol, that was demonstrated to causes ER stress, was ineffective in inducing apoptosis, and the cell survival was guaranteed by autophagy, indicating that apoptosis mediated by ER-stress, requires a functional Bak protein [110].