RAC1 and neoplasm: In the normal mucosa, this pathway serves as a tumor-suppressor, by antagonizing the canonical Wnt-β-catenin signaling pathway (Torres et al., 1996; MacLeod et al., 2007; Ying et al., 2007, 2008; Chien et al., 2009), whereas in advanced tumors it triggers cell migration/invasion by enhancing PI3K-Akt and Rac1 pathways and the formation of actin stress fibers (Nishita et al., 2010; Liu et al., 2013; Zhang et al., 2014).