CDC42 and cancer: The Ras homologous (Rho)-GTPase family proteins, including RhoA, Cdc42, and Rac1, are known to play a key role in cancer development and progression mechanisms, including cell transformation, proliferation, migration, invasion and metastasis by regulating the actin cytoskeleton and cell-cell adhesion (Mitchison and Cramer, 1996, Lauffenburger and Horwitz, 1996, Olson et al., 1998, Ridley, 2000, Fukata and Kaibuchi, 2001).