Similarly, restoration of miR-17/20a functions in murine breast cancer and colon cancer cells mediates the inhibition of the MEKK2–MEK5–ERK5 pathway, leading to the downregulation of MHC-I (H-2D) molecules expressed on tumor cells and enhancing the antitumor activity of NK cells in vivo [71]. The gene discussed is MAP2K5; the disease is breast carcinoma.