KRAS and cancer: The lead molecule allosterically inhibitsthe mitogen-activated protein kinase pathway downstream of K-Ras andtherefore inhibits the growth of KRASG12D-driven cancer cell lines but not non-G12D mutation cancer cell lines.Our results show that the diazo-carboxy ligation spares not only theunreactive Gly12 residue in the K-Ras wild-type protein but also strongnucleophiles such as the Cys12 residue in K-Ras­(G12C).