title: BRCA1 testing should be offered to individuals with triple-negative breast cancer diagnosed below 50 years.
abstract: BACKGROUND
  Triple-negative (TN) tumours are the predominant breast cancer subtype in BRCA1 mutation carriers. Recently, it was proposed that all individuals below 50 years of age with TN breast cancer should be offered BRCA testing. We have evaluated the BRCA1 mutation frequency and the implications for clinical practice of undertaking genetic testing in women with TN breast cancer.
  
  
  METHODS
  We undertook BRCA1 mutation analysis in 308 individuals with TN breast cancer, 159 individuals from unselected series of breast cancer and 149 individuals from series ascertained on the basis of young age and/or family history.
  
  
  RESULTS
  BRCA1 mutations were present in 45 out of 308 individuals. Individuals with TN cancer <50 years had >10% likelihood of carrying a BRCA1 mutation in both the unselected (11 out of 58, 19%) and selected (26 out of 111, 23%) series. However, over a third would not have been offered testing using existing criteria. We estimate that testing all individuals with TN breast cancer <50 years would generate an extra 1200 tests annually in England.
  
  
  CONCLUSIONS
  Women with TN breast cancer diagnosed below 50 years have >10% likelihood of carrying a BRCA1 mutation and are therefore eligible for testing in most centres. However, implementation may place short-term logistical and financial burdens on genetic services.
authors.affiliation: Division of Genetics and Epidemiology, Institute of Cancer Research, 15 Cotswold Road, Sutton, Surrey SM2 5NG, UK.
authors.forename: L
authors.initials: L
authors.lastname: Robertson
authors.forename: H
authors.initials: H
authors.lastname: Hanson
authors.forename: S
authors.initials: S
authors.lastname: Seal
authors.forename: M
authors.initials: M
authors.lastname: Warren-Perry
authors.forename: D
authors.initials: D
authors.lastname: Hughes
authors.forename: I
authors.initials: I
authors.lastname: Howell
authors.forename: C
authors.initials: C
authors.lastname: Turnbull
authors.forename: R
authors.initials: R
authors.lastname: Houlston
authors.forename: S
authors.initials: S
authors.lastname: Shanley
authors.forename: S
authors.initials: S
authors.lastname: Butler
authors.forename: D G
authors.initials: DG
authors.lastname: Evans
authors.forename: G
authors.initials: G
authors.lastname: Ross
authors.forename: D
authors.initials: D
authors.lastname: Eccles
authors.forename: A
authors.initials: A
authors.lastname: Tutt
authors.forename: N
authors.initials: N
authors.lastname: Rahman
mesh_terms: D000367:Age Factors; D019313:BRCA1 Protein / Q000235:genetics*; D001943:Breast Neoplasms / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics* / Q000378:metabolism; D004252:DNA Mutational Analysis; D005260:Female; D056726:Genetic Association Studies; D005820:Genetic Testing; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D009154:Mutation; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism
chemical_list: D019313:BRCA1 Protein; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C492913:BRCA1 protein, human; C508053:ERBB2 protein, human