MAP2K2 and neoplasm: In one model (BoC71) with four SR tumors, we found two acquired KRAS mutations (G12V & G12C in BoC71 C3 & C4, respectively) and one MAP2K2 (Q60P) mutation (BoC71C1), while the fourth tumor (BoC71 C6) did not reveal any alterations known to drive SR.