Graphic representation of the candidate genes involved in fluoropyrimidine pharmacodynamics. A fully interactive version of this pathway is available online at PharmGKB at http://www.pharmgkb.org/search/pathway/5fu/5fu-pd.jsp. DHF, dihydrofolate; DHFR, dihydrofolate reductase; dTMP, deoxythymidine monophosphate; dUMP, deoxyuridine monophosphate; ERCC, excision repair cross complementing; FdUMP, fluorodeoxyuridine monophosphate; FdUTP, fluoro-deoxyuridine triphosphate; FPGS, folylpolyglutamate synthase; FUTP, fluorouridine triphosphate; GGH, Gammaglutamyl hydrolase; MTHFR, methylenetetrahydrofolate reductase; PK, pharmacokinetics; SMUG1, Single-strand selective monofunctional uracil DNA glycosylase 1; TDG, thymidine DNA glycosylase; THF, 5,10-methylene tetrahydrofolate; TYMS, thymidylate synthase.