SNAI1 and neoplasm: Transcriptional factors (TFs) are the primary clues in initiating EMT, such as Snail, TWIST, ZEB, and helix-loop-helix factors Twist1 and Twist2, which by binding to each other can regulate N-cadherin, E-cadherin, and vimentin expression, and also Snail, ZEB1, and ZEB2 are involved in the regulation of cell polarity-related protein expression to enhance the invasive ability of tumor cells (Batlle et al., 2000; Cano et al., 2000; Herranz et al., 2008).