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Evaluation of Polygenic Risk Scores for Breast and Ovarian Cancer Risk Prediction in BRCA1 and BRCA2 Mutation Carriers

Published version
Peer-reviewed

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Authors

Kuchenbaecker, KB 
McGuffog, L 
Barrowdale, D 
Soucy, P 

Abstract

Background: Genome-wide association studies (GWAS) have identified 94 common single-nucleotide polymorphisms (SNPs) associated with breast cancer (BC) risk and 18 associated with ovarian cancer (OC) risk. Several of these are also associated with risk of BC or OC for women who carry a pathogenic mutation in the high-risk BC and OC genes BRCA1 or BRCA2. The combined effects of these variants on BC or OC risk for BRCA1 and BRCA2 mutation carriers have not yet been assessed while their clinical management could benefit from improved personalized risk estimates.

Methods: We constructed polygenic risk scores (PRS) using BC and OC susceptibility SNPs identified through populationbased GWAS: for BC (overall, estrogen receptor [ER]–positive, and ER-negative) and for OC. Using data from 15 252 female BRCA1 and 8211 BRCA2 carriers, the association of each PRS with BC or OC risk was evaluated using a weighted cohort approach, with time to diagnosis as the outcome and estimation of the hazard ratios (HRs) per standard deviation increase in the PRS.

Results: The PRS for ER-negative BC displayed the strongest association with BC risk in BRCA1 carriers (HR = 1.27, 95% confidence interval [CI] = 1.23 to 1.31, P = 8.2 × 10−53). In BRCA2 carriers, the strongest association with BC risk was seen for the overall BC PRS (HR = 1.22, 95% CI = 1.17 to 1.28, P = 7.2 × 10−20). The OC PRS was strongly associated with OC risk for both BRCA1 and BRCA2 carriers. These translate to differences in absolute risks (more than 10% in each case) between the top and bottom AR deciles of the PRS distribution; for example, the OC risk was 6% by age 80 years for BRCA2 carriers at the 10th percentile of the OC PRS compared with 19% risk for those at the 90th percentile of PRS.

Conclusions: BC and OC PRS are predictive of cancer risk in BRCA1 and BRCA2 carriers. Incorporation of the PRS into risk prediction models has promise to better inform decisions on cancer risk management.

Description

Keywords

mutation, brca1 protein, genes, brca1, brca2 gene, single nucleotide polymorphism, receptors, estrogen, breast, diagnosis, breast cancer, ovarian cancer, cancer risk, estrogen receptor negative, genome-wide association study, brca2 mutation

Journal Title

Journal of the National Cancer Institute

Conference Name

Journal ISSN

0027-8874
1460-2105

Volume Title

109

Publisher

Oxford University Press
Sponsorship
Cancer Research Uk (None)
Cancer Research Uk (None)
Cancer Research UK (20861)
National Cancer Institute (U19CA148537)
European Commission (223175)
National Cancer Institute (R01CA128978)
National Cancer Institute (U19CA148065)
Cancer Research UK (12014)
Cancer Research UK (10118)
Cancer Research UK (23382)
Cancer Research Uk (None)
Cancer Research UK (16565)
Cancer Research UK