Rac GEFs such as phosphatidylinositol 3,4,5-triphosphate-dependent Rac exchanger 1 (P-Rex1), T-cell lymphoma invasion and metastasis 1 (Tiam1), and vav guanine nucleotide exchange factor 3 (Vav3) have been also implicated in breast cancer invasion and metastasis (reviewed in Wertheimer et al. [2]). The gene discussed is TIAM1; the disease is breast cancer.