SW203668 is an irreversible inhibitor of stearoyl-CoA desaturase (IC50 = 54 nM). It is selectively cytotoxic to H2122, H460, HCC44, and HCC95 cell lines that express cytochrome P450 (CYP) isoform CYP4F11 over eight other cancer cell lines that lack CYP4F11 in vitro (IC50s = 22-116 and >10,000 nM, respectively) and ectopic expression of CYP4F11 in SW203668-insensitive H1155 cells results in sensitization to SW203668.