title: Association of genetic ancestry with breast cancer in ethnically diverse women from Chicago.
abstract: BACKGROUND
  Non-Hispanic (nH) Black and Hispanic women are disproportionately affected by early onset disease, later stage, and with more aggressive, higher grade and ER/PR negative breast cancers. The purpose of this analysis was to examine whether genetic ancestry could account for these variation in breast cancer characteristics, once data were stratified by self-reported race/ethnicity and adjusted for potential confounding by social and behavioral factors.
  
  
  METHODS
  We used a panel of 100 ancestry informative markers (AIMs) to estimate individual genetic ancestry in 656 women from the "Breast Cancer Care in Chicago" study, a multi-ethnic cohort of breast cancer patients to examine the association between individual genetic ancestry and breast cancer characteristics. In addition we examined the association of individual AIMs and breast cancer to identify genes/regions that may potentially play a role in breast cancer disease disparities.
  
  
  RESULTS
  As expected, nH Black and Hispanic patients were more likely than nH White patients to be diagnosed at later stages, with higher grade, and with ER/PR negative tumors. Higher European genetic ancestry was protective against later stage at diagnosis (OR 0.7 95%CI: 0.54-0.92) among Hispanic patients, and higher grade (OR 0.73, 95%CI: 0.56-0.95) among nH Black patients. After adjustment for multiple social and behavioral risk factors, the association with later stage remained, while the association with grade was not significant. We also found that the AIM SNP rs10954631 on chromosome 7 was associated with later stage (p = 0.02) and higher grade (p = 0.012) in nH Whites and later stage (p = 0.03) in nH Blacks.
  
  
  CONCLUSIONS
  Non-European genetic ancestry was associated with later stage at diagnosis in ethnic minorities. The relation between genetic ancestry and stage at diagnosis may be due to genetic factors and/or unmeasured environmental factors that are overrepresented within certain racial/ethnic groups.
authors.affiliation: Division of Epidemiology and Biostatistics, University of Illinois at Chicago, Chicago, Illinois, United States of America.
authors.forename: Umaima
authors.initials: U
authors.lastname: Al-Alem
authors.affiliation: Division of Epidemiology and Biostatistics, University of Illinois at Chicago, Chicago, Illinois, United States of America.
authors.forename: Garth
authors.initials: G
authors.lastname: Rauscher
authors.affiliation: Department of Surgery, Division of Urology, University of Arizona, Tucson, Arizona, United States of America.
authors.forename: Ebony
authors.initials: E
authors.lastname: Shah
authors.affiliation: Department of Surgery, Division of Urology, University of Arizona, Tucson, Arizona, United States of America.
authors.forename: Ken
authors.initials: K
authors.lastname: Batai
authors.affiliation: Division of Epidemiology and Biostatistics, University of Illinois at Chicago, Chicago, Illinois, United States of America; Department of Pathology, University of Illinois at Chicago, Chicago, Illinois, United States of America.
authors.forename: Abeer
authors.initials: A
authors.lastname: Mahmoud
authors.affiliation: College of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America.
authors.forename: Erin
authors.initials: E
authors.lastname: Beisner
authors.affiliation: Division of Epidemiology and Biostatistics, University of Illinois at Chicago, Chicago, Illinois, United States of America; Edward Hines, Jr. VA Hospital, Hines, Illinois, United States of America.
authors.forename: Abigail
authors.initials: A
authors.lastname: Silva
authors.affiliation: Division of Epidemiology and Biostatistics, University of Illinois at Chicago, Chicago, Illinois, United States of America.
authors.forename: Caryn
authors.initials: C
authors.lastname: Peterson
authors.affiliation: Department of Surgery, Division of Urology, University of Arizona, Tucson, Arizona, United States of America.
authors.forename: Rick
authors.initials: R
authors.lastname: Kittles
mesh_terms: D000328:Adult; D001741:Black or African American; D000368:Aged; D051017:Apoptosis Regulatory Proteins; D001943:Breast Neoplasms / Q000453:epidemiology / Q000208:ethnology / Q000235:genetics*; D002641:Chicago; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D051116:Receptors, Scavenger / Q000235:genetics; D044465:White People
chemical_list: D051017:Apoptosis Regulatory Proteins; C492821:CD5L protein, human; D051116:Receptors, Scavenger