AMACR protein levels and enzyme activity are increased in prostate cancers,11,12 myxofibrosarcomas,13 a subset of colon cancers14 and various other cancers8 and it is widely recognised as a promising drug target.3,8,15–18 Genetic knock-down of AMACR reduces proliferation of cultured cancer cells13,15,16,19 and restores androgen-dependent growth in some prostate cancer cell lines.16 Relatively few chemical inhibitors of AMACR have been reported,17–20 largely due to the lack of a convenient, high-throughput assay. This evidence concerns the gene AMACR and myxofibrosarcoma.