The role of germline genetics in adjuvant aromatase inhibitor (AI) treatment efficacy in ER-positive breast cancer is poorly understood. We employed a two-stage candidate gene approach to examine associations between survival endpoints and common germline variants in 753 endocrine resistance-related genes. For a discovery cohort, we screened the Breast Cancer Association Consortium database (n ≥ 90,000 cases) and retrieved 2789 AI-treated patients. Cox model-based analysis revealed 125 variants associated with overall, distant relapse-free, and relapse-free survival (p-value ≤ 1E-04). In validation analysis using five independent cohorts (n = 8857), none of the six selected candidates representing major linkage blocks at CELA2B/CASP9, NR1I2/GSK3B, LRP1B, and MIR143HG (CARMN) were validated. We discuss potential reasons for the failed validation and replication of published findings, including study/treatment heterogeneity and other limitations inherent to genomic treatment outcome studies. For the future, we envision prospective longitudinal studies with sufficiently long follow-up and endpoints that reflect the dynamic nature of endocrine resistance.
FörderungenOvarian Cancer Research Fund European Union National Cancer Institute Intramural Research Program, National Institutes of Health NIHR Cambridge Biomedical Research Centre Government of Canada through Genome Canada Canadian Institutes of Health Research Breast Cancer Research Foundation Komen Foundation for the Cure Department of Defence Post-Cancer GWAS initiative National Institutes of Health European Community PSRSIIRI-701 grant NIH EU Horizon 2020 Research and Innovation Programme Quebec Breast Cancer Foundation Ministere de l'Economie et de l'Innovation du Quebec through Genome Quebec Cancer Research UK