In the present review article, we have highlighted the role of the newest MAPK member ERK5 in various stages of the metastatic cascade: initiating with EMT, immune escape, increased production of collagen degrading enzymes, MMPs, collagenases, form and structure of the ECM, angiogenesis, survival in blood circulation, and secondary tumor growth at metastatic sites. This evidence concerns the gene MAPK7 and neoplasm.