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Prevalence of BRCA1 and BRCA2 Gene Mutations in Patients With Early-Onset Breast Cancer

Prevalence of BRCA1 and BRCA2 Gene Mutations in Patients With Early-Onset Breast Cancer AbstractBACKGROUND: Mutations in the BRCA1 and BRCA2 genes are found in most families withcases of both breast and ovarian cancer or with many cases of early-onset breast cancer.However, in an outbred population, the prevalence of BRCA1 and BRCA2 mutations in patientswith breast cancer who were unselected for a family history of this disease has not beendetermined. METHODS: Mutations in the BRCA1 and BRCA2 genes were detected in bloodsamples from two population-based series of young patients with breast cancer from Britain.RESULTS: Mutations were detected in 15 (5.9%) of 254 women diagnosed with breastcancer before age 36 years (nine [3.5%] in BRCA1 and six[2.4%] in BRCA2) and in 15 (4.1%) of 363 women diagnosed fromages 36 through 45 years (seven [1.9%] in BRCA1 and eight[2.2%] in BRCA2). Eleven percent (six of 55) of patients with a first-degreerelative who developed ovarian cancer or breast cancer by age 60 years were mutation carriers,compared with 45% (five of 11) of patients with two or more affected first- orsecond-degree relatives. The standardized incidence ratio for breast cancer in mothers and sisterswas 365 (five observed and 1.37 expected) for 30 mutation carriers and 199 (64 observed and32.13 expected) for 587 noncarriers. If we assume recent penetrance estimates, the respectiveproportions of BRCA1 and BRCA2 mutation carriers are 3.1% and 3.0%,respectively, of patients with breast cancer who are younger than age 50 years, 0.49% and0.84% of patients with breast cancer who are age 50 years or older, and 0.11% and0.12% of women in the general population. CONCLUSIONS: Mutations in the BRCA1and BRCA2 genes make approximately equal contributions to early-onset breast cancer inBritain and account for a small proportion of the familial risk of breast cancer. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Journal of the National Cancer Institute Oxford University Press

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References (26)

Publisher
Oxford University Press
Copyright
Oxford University Press
ISSN
0027-8874
eISSN
1460-2105
DOI
10.1093/jnci/91.11.943
Publisher site
See Article on Publisher Site

Abstract

AbstractBACKGROUND: Mutations in the BRCA1 and BRCA2 genes are found in most families withcases of both breast and ovarian cancer or with many cases of early-onset breast cancer.However, in an outbred population, the prevalence of BRCA1 and BRCA2 mutations in patientswith breast cancer who were unselected for a family history of this disease has not beendetermined. METHODS: Mutations in the BRCA1 and BRCA2 genes were detected in bloodsamples from two population-based series of young patients with breast cancer from Britain.RESULTS: Mutations were detected in 15 (5.9%) of 254 women diagnosed with breastcancer before age 36 years (nine [3.5%] in BRCA1 and six[2.4%] in BRCA2) and in 15 (4.1%) of 363 women diagnosed fromages 36 through 45 years (seven [1.9%] in BRCA1 and eight[2.2%] in BRCA2). Eleven percent (six of 55) of patients with a first-degreerelative who developed ovarian cancer or breast cancer by age 60 years were mutation carriers,compared with 45% (five of 11) of patients with two or more affected first- orsecond-degree relatives. The standardized incidence ratio for breast cancer in mothers and sisterswas 365 (five observed and 1.37 expected) for 30 mutation carriers and 199 (64 observed and32.13 expected) for 587 noncarriers. If we assume recent penetrance estimates, the respectiveproportions of BRCA1 and BRCA2 mutation carriers are 3.1% and 3.0%,respectively, of patients with breast cancer who are younger than age 50 years, 0.49% and0.84% of patients with breast cancer who are age 50 years or older, and 0.11% and0.12% of women in the general population. CONCLUSIONS: Mutations in the BRCA1and BRCA2 genes make approximately equal contributions to early-onset breast cancer inBritain and account for a small proportion of the familial risk of breast cancer.

Journal

Journal of the National Cancer InstituteOxford University Press

Published: Jun 2, 1999

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