Activation of these antioxidant enzymes may be one of the reasons for the lack of effect of SELENOM-KD on the proliferative properties of A-172 cancer cells with an increase in the expression of pro-apoptotic genes and the prevention of apoptosis, as evidenced by the absence of changes in the expression of mRNA of other pro-apoptotic genes (CAS-3, CAS-4, BAX, BAK, MAPK-8, MAP3K5), as well as markers of ER stress signaling pathways. Here, MAPK8 is linked to cancer.