MAPK8 and neoplasm: Here, we report that, first, Toll-6 knockdown in RasV12/cell-polarity-defect tumors completely blocks metastasis by effectively reducing JNK signaling; second, the role of JNK activation by Toll-6 is highlighted in the in vitro assay, as Toll-6 knockdown reduced migration of the tumor cells even when discs were not placed (Fig. 3, compare panels K and N; Fig. S9D), suggesting that JNK activation by Toll-6 might be important for general cell migratory behavior.