title: Intrinsic breast tumor subtypes, race, and long-term survival in the Carolina Breast Cancer Study.
abstract: OBJECTIVE
  Previous research identified differences in breast cancer-specific mortality across 4 intrinsic tumor subtypes: luminal A, luminal B, basal-like, and human epidermal growth factor receptor 2 positive/estrogen receptor negative (HER2(+)/ER(-)).
  
  
  METHODS
  We used immunohistochemical markers to subtype 1,149 invasive breast cancer patients (518 African American, 631 white) in the Carolina Breast Cancer Study, a population-based study of women diagnosed with breast cancer. Vital status was determined through 2006 using the National Death Index, with median follow-up of 9 years.
  
  
  RESULTS
  Cancer subtypes luminal A, luminal B, basal-like, and HER2(+)/ER(-) were distributed as 64%, 11%, 11%, and 5% for whites, and 48%, 8%, 22%, and 7% for African Americans, respectively. Breast cancer mortality was higher for participants with HER2(+)/ER(-) and basal-like breast cancer compared with luminal A and B. African Americans had higher breast cancer-specific mortality than whites, but the effect of race was statistically significant only among women with luminal A breast cancer. However, when compared with the luminal A subtype within racial categories, mortality for participants with basal-like breast cancer was higher among whites (HR = 2.0, 95% CI: 1.2-3.4) than African Americans (HR = 1.5, 95% CI: 1.0-2.4), with the strongest effect seen in postmenopausal white women (HR = 3.9, 95% CI: 1.5-10.0).
  
  
  CONCLUSIONS
  Our results confirm the association of basal-like breast cancer with poor prognosis and suggest that basal-like breast cancer is not an inherently more aggressive disease in African American women compared with whites. Additional analyses are needed in populations with known treatment profiles to understand the role of tumor subtypes and race in breast cancer mortality, and in particular our finding that among women with luminal A breast cancer, African Americans have higher mortality than whites.
authors.affiliation: Department of Epidemiology, Gillings School of Global Public Health, University of North Carolina, Chapel Hill, North Carolina 27599, USA.
authors.forename: Katie M
authors.initials: KM
authors.lastname: O'Brien
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Cole
authors.forename: Chiu-Kit
authors.initials: CK
authors.lastname: Tse
authors.forename: Charles M
authors.initials: CM
authors.lastname: Perou
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Carey
authors.forename: William D
authors.initials: WD
authors.lastname: Foulkes
authors.forename: Lynn G
authors.initials: LG
authors.lastname: Dressler
authors.forename: Joseph
authors.initials: J
authors.lastname: Geradts
authors.forename: Robert C
authors.initials: RC
authors.lastname: Millikan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000145:classification / Q000453:epidemiology / Q000208:ethnology* / Q000401:mortality*; D002277:Carcinoma / Q000145:classification / Q000453:epidemiology / Q000208:ethnology* / Q000401:mortality*; D016022:Case-Control Studies; D002423:Cause of Death; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008593:Menopause / Q000378:metabolism / Q000502:physiology; D008875:Middle Aged; D009657:North Carolina / Q000453:epidemiology; D044469:Racial Groups; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D015996:Survival Rate
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human