title: Limited association between a catechol-O-methyltransferase (COMT) polymorphism and breast cancer risk in Japan.
abstract: BACKGROUND
  Catechol-O-methyltransferase (COMT) inactivates the estradiol metabolites, 2-hydroxy estradiol and 4-hydroxy estradiol. To date, three studies in Caucasians and one study in Chinese have been conducted to determine the association with breast cancer risk of a functional polymorphism (G-to-A, Val158Met) of this enzyme, but the results were inconsistent. In order to examine the impact of this polymorphism on breast cancer risk in Japan, a case-control study was conducted, at Aichi Cancer Center Hospital.
  
  
  METHODS
  The cases were 150 patients with histologically confirmed breast cancer who had been diagnosed within 4 years before enrollment at this hospital. The controls were 165 non-cancer patients, mainly from the gastroenterology and breast surgery clinics at the hospital. COMT-H (Val) is the wild-type allele, with high enzyme activity, while the COMT-L (Met) allele has low activity. Genotyping was conducted by a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method.
  
  
  RESULTS
  The allele frequency of COMT-L was 36.0% for cases and 33.0% for controls. Age-adjusted odds ratios relative to the COMT-HH genotype were 1.46 (95% confidence interval [CI], 0.90-2.36) for COMT-HL, and 0.99 (95% CI, 0.49-2.02) for the COMT-LL genotype. Significant odds ratios were not observed for any subgroup stratified by menopausal status, age at menarche, age at birth of first child, body mass index, and breast cancer history of mother and/or sister(s).
  
  
  CONCLUSIONS
  The present study suggested that any association of the COMT polymorphism with breast cancer risk is limited in Japanese.
authors.affiliation: Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, 1-1 Kanokoden, Chikusa-ku, Nagoya 464-8681, Japan. nhamajim@aichi-cc.pref.aichi.jp
authors.forename: N
authors.initials: N
authors.lastname: Hamajima
authors.forename: K
authors.initials: K
authors.lastname: Matsuo
authors.forename: K
authors.initials: K
authors.lastname: Tajima
authors.forename: M
authors.initials: M
authors.lastname: Mizutani
authors.forename: H
authors.initials: H
authors.lastname: Iwata
authors.forename: T
authors.initials: T
authors.lastname: Iwase
authors.forename: S
authors.initials: S
authors.lastname: Miura
authors.forename: H
authors.initials: H
authors.lastname: Oya
authors.forename: Y
authors.initials: Y
authors.lastname: Obata
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000208:ethnology / Q000209:etiology / Q000235:genetics*; D016022:Case-Control Studies; D002394:Catechol O-Methyltransferase / Q000235:genetics* / Q000378:metabolism; D005260:Female; D006801:Humans; D007564:Japan / Q000208:ethnology; D008875:Middle Aged; D016017:Odds Ratio; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic; D012150:Polymorphism, Restriction Fragment Length; D012307:Risk Factors
chemical_list: D002394:Catechol O-Methyltransferase