MAPK8 and neoplasm: The activation of RTKs triggers multiple signaling pathways, including the Rac/MEKK1/MEKK/JNK pathway, Ras/Raf/MEK1/2/ERL/1/2 pathwayPI3K/Akt/NFKB pathway and JAK/STAT pathway.440,441 Multiple molecules were developed to target the downstream effectors of these pathways in order to inhibit tumor cells’ growth and proliferation (Fig. 5).