The best-described tumor-promoting activity of MAPK6 is enhancing the migration/invasion/metastasis of cancer cells, including those of lung, head and neck, breast, and cervix, as well as the human umbilical vein endothelial cells (HUVECs) and vascular smooth muscle cells (VSMCs) (8, 10–15). Here, MAPK6 is linked to neoplasm.