RAS proteins are small GTPases that act as molecular switches, transducing signals from many activated receptors that regulate cell proliferation, survival, and differentiation.Hyperactivation of RAS, either by oncogenic mutations of RAS genes or by mutations of genes that regulate the RAS activity, is common in human cancers.Since the enzymatic activity of RAS is used to turn itselfoffand is inactive in oncogenic RAS, RAS proteins are considered to be "non-targetable" for developing cancer therapies.Identification of alternative targets that block RAS signaling is critical to develop therapies for RAS-related cancer.