According to some scholars, several anti-tumor pathways targeting metabolic enzymes have been identified, including: 5-fluorouracil, Capecitabine, Pemetrexed, and Raltitrexed targeting to Thymidylate synthase (TS); Methotrexate, Pemetrexed targeting to Dihydrofolate reductase (DHFR); Pemetrexed targeting to Glycinamide ribonucleotide formyltransferase (GARFT), et al. This evidence concerns the gene DHFR and neoplasm.