Large scale cancer genome sequencing studies have revealed that mutations in the Rho GTPase family are rare (Refs 125, 126), where generally aberrant activation of this pathway occurs through overexpression of Rho GTPases or by changes in the levels of regulators of Rho activity, including increased activation of GEFs and inactivation or loss of GAPs or GDIs. The gene discussed is RHO; the disease is cancer.