title: Genetic ancestry, self-reported race and ethnicity in African Americans and European Americans in the PCaP cohort.
abstract: BACKGROUND
  Family history and African-American race are important risk factors for both prostate cancer (CaP) incidence and aggressiveness. When studying complex diseases such as CaP that have a heritable component, chances of finding true disease susceptibility alleles can be increased by accounting for genetic ancestry within the population investigated. Race, ethnicity and ancestry were studied in a geographically diverse cohort of men with newly diagnosed CaP.
  
  
  METHODS
  Individual ancestry (IA) was estimated in the population-based North Carolina and Louisiana Prostate Cancer Project (PCaP), a cohort of 2,106 incident CaP cases (2063 with complete ethnicity information) comprising roughly equal numbers of research subjects reporting as Black/African American (AA) or European American/Caucasian/Caucasian American/White (EA) from North Carolina or Louisiana. Mean genome wide individual ancestry estimates of percent African, European and Asian were obtained and tested for differences by state and ethnicity (Cajun and/or Creole and Hispanic/Latino) using multivariate analysis of variance models. Principal components (PC) were compared to assess differences in genetic composition by self-reported race and ethnicity between and within states.
  
  
  RESULTS
  Mean individual ancestries differed by state for self-reporting AA (p = 0.03) and EA (p = 0.001). This geographic difference attenuated for AAs who answered "no" to all ethnicity membership questions (non-ethnic research subjects; p = 0.78) but not EA research subjects, p = 0.002. Mean ancestry estimates of self-identified AA Louisiana research subjects for each ethnic group; Cajun only, Creole only and both Cajun and Creole differed significantly from self-identified non-ethnic AA Louisiana research subjects. These ethnicity differences were not seen in those who self-identified as EA.
  
  
  CONCLUSIONS
  Mean IA differed by race between states, elucidating a potential contributing factor to these differences in AA research participants: self-reported ethnicity. Accurately accounting for genetic admixture in this cohort is essential for future analyses of the genetic and environmental contributions to CaP.
authors.affiliation: Department of Cancer Prevention and Control, Roswell Park Cancer Institute, Buffalo, New York, United States of America. lara.sucheston@roswellpark.org
authors.forename: Lara E
authors.initials: LE
authors.lastname: Sucheston
authors.forename: Jeannette T
authors.initials: JT
authors.lastname: Bensen
authors.forename: Zongli
authors.initials: Z
authors.lastname: Xu
authors.forename: Prashant K
authors.initials: PK
authors.lastname: Singh
authors.forename: Leah
authors.initials: L
authors.lastname: Preus
authors.forename: James L
authors.initials: JL
authors.lastname: Mohler
authors.forename: L Joseph
authors.initials: LJ
authors.lastname: Su
authors.forename: Elizabeth T H
authors.initials: ET
authors.lastname: Fontham
authors.forename: Bernardo
authors.initials: B
authors.lastname: Ruiz
authors.forename: Gary J
authors.initials: GJ
authors.lastname: Smith
authors.forename: Jack A
authors.initials: JA
authors.lastname: Taylor
mesh_terms: D001741:Black or African American / Q000235:genetics*; D000704:Analysis of Variance; D044466:Asian People / Q000235:genetics; D001499:Bayes Theorem; D015331:Cohort Studies; D005787:Gene Frequency; D014644:Genetic Variation; D005838:Genotype; D006630:Hispanic or Latino / Q000235:genetics; D006801:Humans; D008145:Louisiana / Q000453:epidemiology; D008297:Male; D008390:Markov Chains; D009010:Monte Carlo Method; D009657:North Carolina / Q000453:epidemiology; D020641:Polymorphism, Single Nucleotide; D025341:Principal Component Analysis; D011471:Prostatic Neoplasms / Q000208:ethnology* / Q000235:genetics*; D057566:Self Report; D044465:White People / Q000235:genetics*