MiR-155 over-expression can enhance the anti-viral, as well as anti-tumor CD8+ T cell responses in vivo (61). On the other hand, reducing the expression of miR-155 may cause downstream cascades and increase the tendency to generate Th2 cells which secrete type 2 (IL-4, IL-5 and IL-10) cytokines (70). This evidence concerns the gene IL4 and neoplasm.