1. Increased cancer risks for relatives of very early-onset breast cancer cases with and without BRCA1 and BRCA2 mutations.
- Author
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Dite GS, Whittemore AS, Knight JA, John EM, Milne RL, Andrulis IL, Southey MC, McCredie MR, Giles GG, Miron A, Phipps AI, West DW, and Hopper JL
- Subjects
- Adult, Breast Neoplasms epidemiology, Family Health, Female, Humans, Mothers, Risk, Siblings, Age of Onset, Breast Neoplasms genetics, Family, Genes, BRCA1, Genes, BRCA2, Mutation
- Abstract
Background: Little is known regarding cancer risks for relatives of women with very early-onset breast cancer., Methods: We studied 2208 parents and siblings of 504 unselected population-based Caucasian women with breast cancer diagnosed before age 35 years (103 from USA, 124 from Canada and 277 from Australia), 41 known to carry a mutation (24 in BRCA1, 16 in BRCA2 and one in both genes). Cancer-specific standardised incidence ratios (SIRs) were estimated by comparing the number of affected relatives (50% verified overall) with that expected based on incidences specific for country, sex, age and year of birth., Results: For relatives of carriers, the female breast cancer SIRs were 13.13 (95% CI 6.57-26.26) and 12.52 (5.21-30.07) for BRCA1 and BRCA2, respectively. The ovarian cancer SIR was 12.38 (3.1-49.51) for BRCA1 and the prostate cancer SIR was 18.55 (4.64-74.17) for BRCA2. For relatives of non-carriers, the SIRs for female breast, prostate, lung, brain and urinary cancers were 4.03 (2.91-5.93), 5.25 (2.50-11.01), 7.73 (4.74-12.62), 5.19 (2.33-11.54) and 4.35 (1.81-10.46), respectively. For non-carriers, the SIRs remained elevated and were statistically significant for breast and prostate cancer when based on verified cancers., Conclusion: First-degree relatives of women with very early-onset breast cancer are at increased risk of cancers not explained by BRCA1 and BRCA2 mutations.
- Published
- 2010
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