In MDA-MB-231 breast cancer cells treated with CS@FA-SeNPs, caspase-8, caspase-9, and H2AX genes were increased by 1.72-fold, 1.26-fold and 1.52-fold, respectively, compared with the control, and these increases were not found to be statistically significant (p > 0.05). This evidence concerns the gene CASP9 and breast cancer.