Capecitabine is a fluoropyrimidine carbamate that was rationally designed as an orally administered precursor of 5′-deoxy-5-fluorouridine, which is selectively tumor-activated to the cytotoxic agent 5-FU by exploiting the higher levels of thymidine phosphorylase found in tumor tissues compared with normal tissues [6]. This evidence concerns the gene TYMP and neoplasm.