In T cells, miR-155 has been reported to regulate cell lineage decisions, where it suppresses Th2 differentiation (Rodriguez et al., 2007), promotes autoimmune inflammation by enhancing inflammatory T cell development (O’Connell et al., 2010), enhances the effector CD8 T cell immunity, and restrains central memory CD8 differentiation in response to viruses and during cancer (Almanza et al., 2010; Tsai et al., 2013). This evidence concerns the gene CD8A and cancer.