Varlamova et al. (2021) and Turovsky and Varlamova (2021) reported on cytotoxicity effects of Selinium nanoparticles (SeNPs) in cancer cells (A-172 and MCF-7) by activating the mitochondrial apoptosis pathway and by overexpression of pro-apoptotic gene markers such as BCL-2 and caspase 3 and by releasing cytochrome-C into the cytoplasm of cells by increasing the permeability of the mitochondrial membrane, when treated with 5 μg/mL SeNP. The gene discussed is CYCS; the disease is cancer.