title: [Validation of genetic polymorphisms associated to the toxicity of chemotherapy in colorectal cancer patients].
abstract: OBJECTIVE
  To validate the associations previously found in three cohorts of patients from the General University Hospital Gregorio Marañón, between the polymorphisms rs1128503, rs2032582 and rs1045642 of the ABCB1 gene and the hand-foot syndrome and diarrhea in colorectal cancer patients treated with chemotherapy regimes containing Capecitabine and 5-Fluorouracil, respectively, and between the polymorphisms rs2297595 of the DPYD gene and nausea/vomiting, rs11615 of ERCC1 and neutropenia, and rs28399433 CYP2A6 and neutropenia, in colorectal cancer patients treated with FOLFOX or XELOX as adjuvant therapy.
  
  
  METHODS
  Colorectal cancer patients treated with chemotherapy regimes, containing Capecitabine (n = 157), 5-Fluorouracil (n = 99) were included in the study, as well as patients treated with XELOX or FOLFOX (n = 83) as adjuvant therapy. The patients included were recruited from the Doce de Octubre University Hospital and from the Gregorio Marañón General University Hospital, and signed the informed consent form. DNA was obtained from blood samples. Genotyping was carried out with SNaPshot. Contingency tables were created for analyzing the associations between the genotypes and the adverse reactions.
  
  
  RESULTS
  None of the associations previously identified was replicated in the validation cohort.
  
  
  CONCLUSIONS
  Pharmacogenetic studies with a limited sample size must be validated with bigger cohorts, if possible by means of multicentre studies, reducing the variables to the maximum and should never be used in clinical practice without validation.
authors.affiliation: Servicio de Farmacia. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón. Madrid.. llopezf.hgugm@gmail.com.
authors.forename: L
authors.initials: L
authors.lastname: Cortejoso
authors.affiliation: Servicio de Farmacia. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón. Madrid.. llopezf.hgugm@gmail.com.
authors.forename: M I
authors.initials: MI
authors.lastname: García
authors.affiliation: Servicio de Oncología Médica. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón. Madrid.. llopezf.hgugm@gmail.com.
authors.forename: P
authors.initials: P
authors.lastname: García-Alfonso
authors.affiliation: Servicio de Oncología Médica. Hospital Universitario Doce de Octubre. Madrid.. llopezf.hgugm@gmail.com.
authors.forename: C
authors.initials: C
authors.lastname: Grávalos
authors.affiliation: Servicio de Oncología Médica. Hospital Universitario Doce de Octubre. Madrid.. llopezf.hgugm@gmail.com.
authors.forename: L
authors.initials: L
authors.lastname: Robles
authors.affiliation: Servicio de Farmacia. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón. Madrid.. llopezf.hgugm@gmail.com.
authors.forename: E
authors.initials: E
authors.lastname: González-Haba
authors.affiliation: Servicio de Farmacia. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón. Madrid.. llopezf.hgugm@gmail.com.
authors.forename: M
authors.initials: M
authors.lastname: Sanjurjo
authors.affiliation: Servicio de Farmacia. Hospital General Universitario Gregorio Marañón. Instituto de Investigación Sanitaria Gregorio Marañón. Madrid.. llopezf.hgugm@gmail.com.
authors.forename: L A
authors.initials: LA
authors.lastname: López-Fernández
mesh_terms: D000368:Aged; D000970:Antineoplastic Agents / Q000009:adverse effects*; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000235:genetics*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011446:Prospective Studies; D012189:Retrospective Studies
chemical_list: D000970:Antineoplastic Agents