KRAS and cancer: One of such hot spot mutations, KRAS p.G12R, is found in 17% of pancreatic ductal adenocarcinoma(PDAC) patients, accounting for more than 9,000 new cancer patientsper year in the U.S. alone.4,12 We reasoned that covalentengagement of the acquired arginine (Arg12) could impart both potencyand selectivity and enable the direct targeting of K-Ras(G12R).