title: A new DPYD genotyping assay for improving the safety of 5-fluorouracil therapy.
abstract: BACKGROUND
  Chemotherapeutic use of 5-fluorouracil (5FU) is compromised by 10-20% of patients developing severe toxicity. Recently described genetic variation in dihydropyrimidine dehydrogenase (DPYD) has been shown to be a major predictor of 5FU toxicity. Here, we describe a new genotyping assay for routine clinical use that covers all the major DPYD risk variants.
  
  
  METHODS
  Genomic regions targeting DPYD risk variants (c.1129-5923C>G, c.1679T>G/A, c.1905+1G>A, c.2846A>T) and additional markers (c.234-123G>C, c.496A>G, c.775A>G) were amplified in a multiplex PCR reaction. The subsequent steps including allele-specific primer extension, hybridization of the primers to a microarray, scanning of the array, and data analysis were automated within the INFINITI® Analyzer (AutoGenomics). The assay was validated by analyzing 107 blood samples obtained from patients previously re-sequenced for the DPYD.
  
  
  RESULTS
  The genotypes obtained with the developed assay were 100% concordant with the re-sequencing. The procedure is suitable for routine clinical use since the results are obtained within one day. For heterozygous risk variant carriers (~7% of Europeans), the treatment can be adjusted by 5FU dose reduction, whereas carriers of two risk alleles should be treated with an alternative therapy.
  
  
  CONCLUSIONS
  The developed assay provides a novel tool to improve the safety of commonly used 5FU-based chemotherapies.
authors.affiliation: Institute of Clinical Chemistry, Inselspital, Bern University Hospital, and University of Bern, Bern, Switzerland. johanna.sistonen@insel.ch
authors.forename: Johanna
authors.initials: J
authors.lastname: Sistonen
authors.forename: Chingying
authors.initials: C
authors.lastname: Smith
authors.forename: Yung-Kang
authors.initials: YK
authors.lastname: Fu
authors.forename: Carlo R
authors.initials: CR
authors.lastname: Largiadèr
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use*; D042943:Dihydrouracil Dehydrogenase (NADP) / Q000235:genetics*; D005472:Fluorouracil / Q000009:adverse effects / Q000627:therapeutic use*; D005838:Genotype; D060005:Genotyping Techniques; D006801:Humans; D012449:Safety
chemical_list: D042943:Dihydrouracil Dehydrogenase (NADP); D005472:Fluorouracil