RHOA and melanoma: Cancer cells, including melanoma, can individually invade a 3D environment in either a mesenchymal mode, which depends on integrin-mediated adhesion and extracellular protease activity, or in an amoeboid mode that is independent of integrins and localised proteolysis, and is also characterised by largely dissociated microtubules and high RhoA-ROCK-dependent contractility [36,37,38].