In vitro investigations using MCF-7 and MDA-MB-231 BC cells revealed that oleuropein treatment induced cell cycle arrest at the G1 and S phases [202]; its effects on MDA-MB-231 and MDA-MB-468 BC cell lines include cell proliferation inhibition, apoptosis induction through S-phase arrest, and caspase-1, -4, and -14 expression [203]. This evidence concerns the gene CASP1 and breast cancer.