title: Atypical toxicity associated with 5-Fluororacil in a DPD-deficient patient with pancreatic cancer. Is ethnicity a risk factor?
abstract: BACKGROUND
  Fluoropyrimidines constitute the backbone of chemotherapy regimens for GI tumors, including pancreatic cancer where it is used either as a radiosensitizer or as second-line after failing gemcitabine. While normal dihydropyrimidine dehydrogenase (DPD) enzyme activity is rate limiting in 5-fluorouracil (5-FU) catabolism, its deficiency could increase concentrations of bioavailable 5-FU anabolic products leading to 5-FU related toxicity syndrome. The most common toxicities include myelosuppression, stomatitis, neuropathy, and diarrhea. The prevalence of this autosommal codominently inherited pharmacogenetic syndrome is approximately 3-5% in the Caucasian population and 8% in the African-American population.
  
  
  METHODS
  We present here a case of an African-American patient with pancreatic cancer who developed a desquamative skin rash on the face, trunk, and forearms as the worst rash (grade 3) following 5-FU bolus that led to the investigation of DPD enzyme. Measurement of DPD activity by radioisotopic assay methods described previously revealed an abnormally low level of 0.087 nmol/min/mg protein (reference range: 0.182-0.688 nmol/min/mg protein). She was treated toxicity with intravenous steroids and antihistamine therapy. Further 5-FU therapy was discontinued.
  
  
  CONCLUSIONS
  This case suggest that the pattern of toxicities associated with 5-FU can vary, especially in patients with different ethnic backgrounds (whites versus non-whites). These findings become of further importance as our recent study suggests that DPD deficiency may be more common among African-Americans.
authors.forename: Muhammad Wasif
authors.initials: MW
authors.lastname: Saif
authors.forename: Sandra
authors.initials: S
authors.lastname: Seller
authors.forename: Robert B
authors.initials: RB
authors.lastname: Diasio
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000201:enzymology; D000368:Aged; D000964:Antimetabolites, Antineoplastic / Q000009:adverse effects*; D054067:Dihydropyrimidine Dehydrogenase Deficiency; D003875:Drug Eruptions / Q000208:ethnology* / Q000209:etiology; D005260:Female; D005472:Fluorouracil / Q000009:adverse effects*; D006801:Humans; D010190:Pancreatic Neoplasms / Q000188:drug therapy / Q000201:enzymology
chemical_list: D000964:Antimetabolites, Antineoplastic; D005472:Fluorouracil