A hotspot mutation targeting the R-RAS2 GTPase acts as a potent oncogenic driver in a wide spectrum of tumors

A missense change in RRAS2 (Gln72 to Leu), analogous to the Gln61-to-Leu mutation of RAS oncoproteins, has been identified as a long-tail hotspot mutation in cancer and Noonan syndrome. However, the relevance of this mutation for in vivo tumorigenesis remains understudied. Here we show, using an inducible knockin mouse model, that R-Ras2Q72L triggers rapid development of a wide spectrum of tumors when somatically expressed in adult tissues. These tumors show limited overlap with those originated by classical Ras oncogenes. R-Ras2Q72L-driven tumors can be classified into different subtypes according to therapeutic susceptibility. Importantly, the most relevant R-Ras2Q72L-driven tumors are dependent on mTORC1 but independent of phosphatidylinositol 3-kinase-, MEK-, and Ral guanosine diphosphate (GDP) dissociation stimulator. This pharmacological vulnerability is due to the extensive rewiring by R-Ras2Q72L of pathways that orthogonally stimulate mTORC1 signaling. These findings demonstrate that RRAS2Q72L is a bona fide oncogenic driver and unveil therapeutic strategies for patients with cancer and Noonan syndrome bearing RRAS2 mutations. [Display omitted] •RRAS2Q72L is a long-tail hotspot mutation identified in pan-cancer data•R-RAS2Q72L behaves as a potent oncogenic driver for a large spectrum of tumors•R-RAS2Q72L triggers cell-type-specific pathobiological programs•R-RAS2Q72L-driven tumors show drug vulnerabilities of potential clinical interest Fernández-Pisonero et al. demonstrate, using a mouse model, that the Q72L mutation of RRAS2 found in human tumors acts as a potent oncogenic driver in a diverse spectrum of tissues. This activity is quite different from the signaling and tumor types typically induced by classical RAS oncoproteins.