title: Increased risk of breast cancer associated with CHEK2*1100delC.
abstract: OBJECTIVE
  CHEK2*1100delC heterozygosity has been associated with increased risk of breast, prostate, and colorectal cancer in case-control studies. We tested the hypothesis that CHEK2*1100delC heterozygosity in the general population increases the risk of cancer in general, and breast, prostate, and colorectal cancer in particular.
  
  
  METHODS
  We performed a prospective study of 9,231 individuals from the Danish general population, who were observed for 34 years, and we performed a case-control study including 1,101 cases of breast cancer and 4,665 controls.
  
  
  RESULTS
  Of the general population, 0.5% were heterozygotes and 99.5% were noncarriers. In the prospective study, multifactorially adjusted hazard ratios by CHEK2*1100delC heterozygosity versus noncarriers were 1.2 (95% CI, 0.7 to 2.1) for all cancers, 3.2 (95% CI, 1.0 to 9.9) for breast cancer, 2.3 (95% CI, 0.6 to 9.5) for prostate cancer, and 1.6 (95% CI, 0.4 to 6.5) for colorectal cancer. In the case-control study, age-matched odds ratio for breast cancer by CHEK2*1100delC heterozygosity versus noncarriers was 2.6 (95% CI, 1.3 to 5.4). The absolute 10-year risk of breast cancer in CHEK2*1100delC heterozygotes amounted to 24% in women older than 60 years undergoing hormone replacement therapy, with a body mass index of 25 kg/m2 or higher.
  
  
  CONCLUSIONS
  CHEK2*1100delC heterozygosity is associated with a three-fold risk of breast cancer in women in the general population.
authors.affiliation: Department of Clinical Biochemistry, Herlev University Hospital, Herlev, Denmark.
authors.forename: Maren
authors.initials: M
authors.lastname: Weischer
authors.forename: Stig Egil
authors.initials: SE
authors.lastname: Bojesen
authors.forename: Anne
authors.initials: A
authors.lastname: Tybjaerg-Hansen
authors.forename: Christen Kirk
authors.initials: CK
authors.lastname: Axelsson
authors.forename: Børge Grønne
authors.initials: BG
authors.lastname: Nordestgaard
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000235:genetics*; D016022:Case-Control Studies; D064447:Checkpoint Kinase 2; D015179:Colorectal Neoplasms / Q000235:genetics*; D003718:Denmark; D005260:Female; D017353:Gene Deletion; D020022:Genetic Predisposition to Disease; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011471:Prostatic Neoplasms / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D012306:Risk
chemical_list: D064447:Checkpoint Kinase 2; C578634:CHEK2 protein, human; D017346:Protein Serine-Threonine Kinases