DPYD and esophageal cancer: Some molecular markers have been identified for tailored treatment of esophageal cancer, including platinum related markers [glutathione S-transferase π (GST-π), excision repair cross-complementing 1 (ERCC1) and p-glycoprotein (P-gp)], 5-FU related markers [thymidylate synthase (TS) and dihydropyrimidine dehydrogenase (DPD)] and some proteins in various DNA repair pathways [7]–[9].