Figure 2. Summary of Snail signaling in prostate cancer. Snail can be activated by growth factors such as TGF-β, EGF, VEGF-A and GDF-9; extracellular matrix proteins such as collagen and periostin; hormones such as DHT; kinases such as PI3-K and PAK1; lipid molecules such as PGE(2); enzymes such as aldehyde dehydrogenase 7A1 and LIV-1 zinc finger protein. On the other hand, factors that can negatively regulate Snail include hormones such as 3β-Adiol, which inhibits Snail through ER-β, GSK-3β, PKD1 and miR-29b micro-RNA. Activated Snail can subsequently upregulate or downregulate various genes to increase migratory and invasive �potential.