title: Effect of CYP2D6 polymorphisms on breast cancer recurrence.
abstract: BACKGROUND
  Previous studies evaluating the effect of cytochrome P450 2D6 (CYP2D6) polymorphisms on outcomes of adjuvant tamoxifen therapy have been conflicting due to differences in study design, concomitant medications that alter CYP2D6 metabolism, and tamoxifen adherence.
  
  
  METHODS
  The authors performed CYP2D6 genotyping from whole blood and fresh frozen tumor samples (n 106) in patients at The University of Texas MD Anderson Cancer Center who were receiving, or had received, tamoxifen as adjuvant therapy for early breast cancer (EBC), using the AmpliChip CYP450 Test. Each patient's medical history was assessed for drugs that affected CYP2D6. Fifty-five patients who had experienced breast cancer recurrence were matched (by date of diagnosis, menopausal status, clinical stage [TNM Staging System], and race) to patients without recurrence.
  
  
  RESULTS
  Unadjusted for other patient characteristics, the odds ratio for disease recurrence associated with CYP2D6 functional status was 1.0 (95% confidence interval, 0.35-2.85). After adjustment for stage, CYP2D6 inhibitors (moderate or strong vs none), and follow-up time, no significant association was found between CYP2D6 genotype and breast cancer recurrence in patients who were treated with adjuvant tamoxifen for EBC.
  
  
  CONCLUSIONS
  This case-control study demonstrated no significant effect of CYP2D6 genotype on risk of recurrence in breast cancer patients who received adjuvant tamoxifen therapy.
authors.affiliation: Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.
authors.forename: Phuong K
authors.initials: PK
authors.lastname: Morrow
authors.forename: Ruben
authors.initials: R
authors.lastname: Serna
authors.forename: Kristine
authors.initials: K
authors.lastname: Broglio
authors.forename: Lajos
authors.initials: L
authors.lastname: Pusztai
authors.forename: D Michelle
authors.initials: DM
authors.lastname: Nikoloff
authors.forename: Grantland R
authors.initials: GR
authors.lastname: Hillman
authors.forename: Marcel
authors.initials: M
authors.lastname: Fontecha
authors.forename: Rui
authors.initials: R
authors.lastname: Li
authors.forename: Laura
authors.initials: L
authors.lastname: Michaud
authors.forename: Gabriel
authors.initials: G
authors.lastname: Hortobagyi
authors.forename: Ana M
authors.initials: AM
authors.lastname: Gonzalez-Angulo
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage; D001943:Breast Neoplasms / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D002277:Carcinoma / Q000453:epidemiology / Q000235:genetics* / Q000473:pathology / Q000628:therapy; D016022:Case-Control Studies; D015331:Cohort Studies; D019389:Cytochrome P-450 CYP2D6 / Q000235:genetics*; D065690:Cytochrome P-450 CYP2D6 Inhibitors; D004791:Enzyme Inhibitors / Q000008:administration & dosage; D005260:Female; D005500:Follow-Up Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D008408:Mastectomy / Q000706:statistics & numerical data; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology / Q000235:genetics*; D011110:Polymorphism, Genetic / Q000502:physiology*; D013629:Tamoxifen / Q000008:administration & dosage
chemical_list: D065690:Cytochrome P-450 CYP2D6 Inhibitors; D004791:Enzyme Inhibitors; D013629:Tamoxifen; D019389:Cytochrome P-450 CYP2D6