title: The Effect of the CYP1A1*2A Allele on Colorectal Cancer Susceptibility in a British Population.
abstract: OBJECTIVE
  Colorectal cancer (CRC) is a major health problem despite recent improvements in overall survival rates. Genetic polymorphisms affecting carcinogen biotransformation or DNA repair play pivotal roles in the carcinogenesis process. CYP1A1*2A (6235 T/C, rs4646903, MspI) is thought to be associated with an increased risk of CRC because of its role in metabolic activation of polycyclic aromatic hydrocarbons; however, the results of previous studies are conflicting. In this study, a possible association between the CYP1A1*2A allele and CRC and the effect of cigarette smoking on this risk were examined in a British population.
  
  
  METHODS
  A prospective case-control study including 200 cases and 254 age-and-sex-matched controls was conducted with British participants from the north-east of England. Genotyping of the CYP1A1*2A allele was performed using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.
  
  
  RESULTS
  CYP1A1*2A was not associated with CRC development (OR = 1.566; 95% confidence interval [CI] = 0.90-2.73; p = 0.12). However, it was observed that C allele-carrying individuals who had smoked within the past 5 years had a significant risk of CRC (OR = 2.28; 95% CI = 1.07-4.86; p = 0.043).
  
  
  CONCLUSIONS
  These data are of interest in understanding CRC etiology and identifying an individual's risk of developing CRC. However, a full evaluation of an association between CYP1A1*2A and cancer susceptibility in Europeans is difficult and will require a larger number of participants.
authors.affiliation: 1 Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Istanbul University , Istanbul, Turkey .
authors.forename: Ezgi
authors.initials: E
authors.lastname: Öztaş
authors.affiliation: 1 Department of Pharmaceutical Toxicology, Faculty of Pharmacy, Istanbul University , Istanbul, Turkey .
authors.forename: Gül
authors.initials: G
authors.lastname: Özhan
authors.affiliation: 2 Institute of Cellular Medicine, Newcastle University , Newcastle upon Tyne, United Kingdom .
authors.forename: Ann K
authors.initials: AK
authors.lastname: Daly
mesh_terms: D000483:Alleles; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000201:enzymology* / Q000235:genetics*; D019363:Cytochrome P-450 CYP1A1 / Q000235:genetics* / Q000378:metabolism; D004739:England; D005260:Female; D005787:Gene Frequency; D056726:Genetic Association Studies; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D011110:Polymorphism, Genetic; D011446:Prospective Studies; D012307:Risk Factors; D012907:Smoking / Q000235:genetics / Q000378:metabolism; D044465:White People / Q000235:genetics
chemical_list: C569463:CYP1A1 protein, human; D019363:Cytochrome P-450 CYP1A1