RAC1 and pancreatic neoplasm: The well-known function of Vav1 as the tyrosine phosphorylation–dependent GEF activity for Rac1 (Crespo et al, 1997) was previously shown to be linked to an increase in tumorigenic properties of pancreatic cancer (Fernandez-Zapico et al, 2005; Lazer et al, 2010).