B7-H4 overexpression activates a variety of signaling pathways, such as the NF-κB, ERK1/2, AKT/STAT3 and PI3K/AKT/mTOR pathways, to promote epithelial-mesenchymal transition (EMT) and invasion of cancer cells [20, 22, 59, 60]. Here, MAPK3 is linked to cancer.