Ras homolog gene family, member B, also known as RHOB, is a protein which in humans is encoded by the RHOB gene.RHOB is a member of the Rho GTP-binding protein family.Mediates apoptosis in neoplastically transformed cells after DNA damage. It is not necessary for development but affects cell adhesion and growth factor signaling in transformed cells. It plays a negative role in tumorigenesis as deletion causes tumor formation. It involved in intracellular protein trafficking of a number of proteins, and serves as a microtubule-dependent signal that is required for the myosin contractile ring formation during cell cycle cytokinesis. Required for genotoxic stress-induced cell death in breast cancer cells.