In conclusion, our findings demonstrated that the dual inhibition of CDK4 and FYN resulted in selective cell death of KRAS-mutant CRC cells and that ON123300, a dual CDK4/FYN inhibitor, exerted specific and potent anticancer activity against KRAS-mutant CRC both in vitro and in vivo and without adverse side effects. This evidence concerns the gene FYN and colorectal carcinoma.