TGFB1 and neoplasm: Apart from the TGF-β1/Smad pathway, TGF-β1 can also carry out its role in tumor progression by activating non-Smad pathways, such as the phosphatidylinositol-3 kinase (PI3K), extracellular signal-regulated kinase [ERK, mitogen-activated protein kinase (MAPK)], c-Jun NH2-terminal kinase (JNK) and p38 MAPK pathways and Rho GTPases (4).