MAPK8 and neoplasm: We have shown previously that Fos is required downstream of JNK to promote cell migration and tumor cell invasiveness by upregulating Matrix metalloprotease 1 (MMP1) and the actin cross-linking protein FilaminA/Cheerio, which cooperatively disorganize epithelia, allowing cells to breach the basement membrane and spread to secondary sites (Uhlirova and Bohmann, 2006; Külshammer and Uhlirova, 2013).