SOS1 and neoplasm: To address this question, we used here an orthotopic model of LUAD tumorigenesis using KPB6 mouse LUAD cells harboring KRASG12D and p53 mutations46 where we analyzed the role of SOS1 and SOS2 in tumor cell homing and lung colonization after eliminating these RAS-GEFs in either the recipient mice or in the injected KPB6 tumor cells.