CD8A and digestive system neoplasm: Additionally, we found that gastrointestinal tumors obtained from mice treated with MK2 KO CD8+ T cells are characterized by increased expression of genes related to programmed cell death such as Casp3, Fas and Fasl. Among several caspases, CASP3 is a frequently activated protease leading to the specific cleavage of numerous proteins and coordinating the degradation of cellular structures (30).