MAPK8 and cancer: We found that the luciferase activity from a synthetic TEAD-dependent YAP/TAZ-responsive reporter, as a direct readout of Hippo activity, was decreased by 92% in U87MG-sh-USP39-1 cells, whereas the luciferase activities of the other six cancer pathways, including MAPK/ERK, MAPK/JNK, NFκB, Notch, TGFβ, and Wnt, remained unchanged (Fig. 4a).