title: CHEK2*1100delC genotyping for clinical assessment of breast cancer risk: meta-analyses of 26,000 patient cases and 27,000 controls.
abstract: OBJECTIVE
  CHEK2*1100delC heterozygosity may be associated with an increased risk of breast cancer; however, it is unclear whether the evidence is sufficient to recommend genotyping in clinical practice.
  
  
  METHODS
  We identified studies on CHEK2*1100delC heterozygosity and the risk of unselected, early-onset, and familial breast cancer through comprehensive, computer-based searches of PubMed, EMBASE, and Web of Science. Aggregated risk estimates were compared with previous estimates for BRCA1 and BRCA2 mutation heterozygotes.
  
  
  RESULTS
  By using fixed-effect models for CHEK2*1100delC heterozygotes versus noncarriers, we found aggregated odds ratios of 2.7 (95% CI, 2.1 to 3.4) for unselected breast cancer, 2.6 (95% CI, 1.3 to 5.5) for early-onset breast cancer, and 4.8 (95% CI, 3.3 to 7.2) for familial breast cancer. For familial breast cancer, this corresponds to a cumulative risk of breast cancer at age 70 years in CHEK2*1100delC heterozygotes of 37% (95% CI, 26% to 56%), which compares with similar previous estimates of 57% (95% CI, 47% to 66%) for BRCA1 mutation heterozygotes and 49% (95% CI, 40% to 57%) for BRCA2 mutation heterozygotes.
  
  
  CONCLUSIONS
  These meta-analyses emphasize that CHEK2*1100delC is an important breast cancer-predisposing gene, which increases the risk three- to five-fold. Because the cumulative risk of breast cancer at age 70 years among familial patient cases for CHEK2*1100delC heterozygotes is almost as high as that for BRCA1 and BRCA2 mutation heterozygotes, genotyping for CHEK2*1100delC should be considered together with BRCA1 and BRCA2 mutation screening in women with a family history of breast cancer.
authors.affiliation: Department of Clinical Biochemistry, Herlev University Hospital, Herlev Ringvej 75, Herlev, Denmark.
authors.forename: Maren
authors.initials: M
authors.lastname: Weischer
authors.forename: Stig Egil
authors.initials: SE
authors.lastname: Bojesen
authors.forename: Christina
authors.initials: C
authors.lastname: Ellervik
authors.forename: Anne
authors.initials: A
authors.lastname: Tybjaerg-Hansen
authors.forename: Børge Grønne
authors.initials: BG
authors.lastname: Nordestgaard
mesh_terms: D000368:Aged; D051017:Apoptosis Regulatory Proteins; D019313:BRCA1 Protein / Q000235:genetics; D024682:BRCA2 Protein / Q000235:genetics; D001943:Breast Neoplasms / Q000235:genetics*; D016022:Case-Control Studies; D064447:Checkpoint Kinase 2; D005260:Female; D006580:Genetic Carrier Screening; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005820:Genetic Testing; D005838:Genotype; D006801:Humans; D009154:Mutation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D018570:Risk Assessment
chemical_list: D051017:Apoptosis Regulatory Proteins; C118024:BLID protein, human; D019313:BRCA1 Protein; C492913:BRCA1 protein, human; D024682:BRCA2 Protein; C551750:BRCA2 protein, human; D064447:Checkpoint Kinase 2; C578634:CHEK2 protein, human; D017346:Protein Serine-Threonine Kinases