The most common GEFs implicated in cancer are T-cell lymphoma invasion and metastasis 1 (Tiam1), Trio, Vav1/2/3, Ect2, Phosphatidylinositol 3,4,5-trisphosphate (PIP3)-dependent Rac exchanger 1 (P-Rex1), and Dock1 (Wertheimer et al., 2012; Porter et al., 2016; Kazanietz and Caloca, 2017). The gene discussed is PREX1; the disease is cancer.