Considering the important role of caspases 8 and 10 in the initiation of apoptosis via the extrinsic pathway, we evaluated the effects of the novel selenocompound EDA-71 and cisplatin on the activation of these initiatory caspases in MCF-7 and MDA-MB-231 breast cancer cells after 24 h of exposure to these compounds at concentrations of 1.5 and 3 μM. This evidence concerns the gene CASP8 and breast cancer.