TGF-β may also signal through Smad-independent signaling cascades (e.g., Rho-like guanosine triphosphatases, p38, mitogen-activated protein kinase [MAPK], phosphatidylinositol-3-kinase or c-Jun-N-terminal kinase) and induce an epithelial-to-mesenchymal transition (EMT)—which is a key process in the formation of cancer metastasis—of tumor cells, leading to enhanced tumor cell migration and invasion [66,67,68,69,70]. This evidence concerns the gene TGFB1 and cancer.