title: Genetic ancestry and risk of breast cancer among U.S. Latinas.
abstract: U.S. Latinas have a lower incidence of breast cancer compared with non-Latina White women. This difference is partially explained by differences in the prevalence of known risk factors. Genetic factors may also contribute to this difference in incidence. Latinas are an admixed population with most of their genetic ancestry from Europeans and Indigenous Americans. We used genetic markers to estimate the ancestry of Latina breast cancer cases and controls and assessed the association with genetic ancestry, adjusting for reproductive and other risk factors. We typed a set of 106 ancestry informative markers in 440 Latina women with breast cancer and 597 Latina controls from the San Francisco Bay area and estimated genetic ancestry using a maximum likelihood method. Odds ratios (OR) and 95% confidence intervals (95% CI) for ancestry modeled as a continuous variable were estimated using logistic regression with known risk factors included as covariates. Higher European ancestry was associated with increased breast cancer risk. The OR for a 25% increase in European ancestry was 1.79 (95% CI, 1.28-2.79; P<0.001). When known risk factors and place of birth were adjusted for, the association with European ancestry was attenuated but remained statistically significant (OR, 1.39; 95% CI, 1.06-2.11; P=0.013). Further work is needed to determine if the association is due to genetic differences between populations or possibly due to environmental factors not measured.
authors.affiliation: Division of General Internal Medicine and Lung Biology Center, Department of Medicine, University of California, San Francisco, CA 94143-1732, USA. laura.fejerman@ucsf.edu
authors.forename: Laura
authors.initials: L
authors.lastname: Fejerman
authors.forename: Esther M
authors.initials: EM
authors.lastname: John
authors.forename: Scott
authors.initials: S
authors.lastname: Huntsman
authors.forename: Kenny
authors.initials: K
authors.lastname: Beckman
authors.forename: Shweta
authors.initials: S
authors.lastname: Choudhry
authors.forename: Eliseo
authors.initials: E
authors.lastname: Perez-Stable
authors.forename: Esteban González
authors.initials: EG
authors.lastname: Burchard
authors.forename: Elad
authors.initials: E
authors.lastname: Ziv
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology / Q000208:ethnology* / Q000235:genetics*; D002140:California / Q000453:epidemiology; D016022:Case-Control Studies; D005260:Female; D020022:Genetic Predisposition to Disease; D006630:Hispanic or Latino / Q000235:genetics*; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide