The 3,4,5-trimethoxyphenyl group is a commonly encountered substructure in ATP-competitive inhibitors of protein kinases and in a variety of other molecules with biological activity, such as the antibiotic trimethoprim, the antihypertensive reserpine, the anti-inflammatory colchicine, and the DHFR-inhibitor trimetrexate for the treatment of leiomyosarcoma [29]. This evidence concerns the gene DHFR and leiomyosarcoma.