YN14 is a highly potent and selective KRASG12C proteolysis targeting chimera (PROTAC) capable of forming a stable KRASG12C: YN14: VHL ternary complex with low binding free energy (ΔG). It exhibits antiproliferative effects, significantly inhibiting the growth of KRASG12C-mutant cancer cells, and demonstrates tumor regression with tumor growth inhibition (TGI%) rates exceeding 100% in the MIA PaCa-2 xenograft model.