The RAS oncogenes were identified almost 20 years ago. Since then, we have learnt that they are members of a large family of small GTPases that bind GTP and hydrolyse it to GDP. This is then exchanged for GTP and the cycle is repeated. The switching between these two states regulates a wide range of cellular processes. A branch of the RAS family--the RHO proteins--is also involved in cancer, but what is the role of these proteins and would they make good therapeutic targets?