CDC42 and neoplasm: In addition to maintaining multi-cellular aggregates of tumour cells, studies in N-cadherin-expressing non-tumour cells have demonstrated that N-cadherin also promotes collective cell migration by polarising Rho-family GTPase signalling (e.g. Rac1 and cdc42), known to co-ordinate cytoskeletal remodelling in collectively migrating cells [100, 101].