title: Triple-negative breast cancers are increased in black women regardless of age or body mass index.
abstract: BACKGROUND
  We investigated clinical and pathologic features of breast cancers (BC) in an unselected series of patients diagnosed in a tertiary care hospital serving a diverse population. We focused on triple-negative (Tneg) tumours (oestrogen receptor (ER), progesterone receptor (PR) and HER2 negative), which are associated with poor prognosis.
  
  
  METHODS
  We identified female patients with invasive BC diagnosed between 1998 and 2006, with data available on tumor grade, stage, ER, PR and HER2 status, and patient age, body mass index (BMI) and self-identified racial/ethnic group. We determined associations between patient and tumour characteristics using contingency tables and multivariate logistic regression.
  
  
  RESULTS
  415 cases were identified. Patients were racially and ethnically diverse (born in 44 countries, 36% white, 43% black, 10% Hispanic and 11% other). 47% were obese (BMI > 30 kg/m2). 72% of tumours were ER+ and/or PR+, 20% were Tneg and 13% were HER2+. The odds of having a Tneg tumour were 3-fold higher (95% CI 1.6, 5.5; p = 0.0001) in black compared with white women. Tneg tumours were equally common in black women diagnosed before and after age 50 (31% vs 29%; p = NS), and who were obese and non-obese (29% vs 31%; p = NS). Considering all patients, as BMI increased, the proportion of Tneg tumours decreased (p = 0.08).
  
  
  CONCLUSIONS
  Black women of diverse background have 3-fold more Tneg tumours than non-black women, regardless of age and BMI. Other factors must determine tumour subtype. The higher prevalence of Tneg tumours in black women in all age and weight categories likely contributes to black women's unfavorable breast cancer prognosis.
authors.affiliation: Department of Medicine, Boston University Medical Center, Boston, MA 02118, USA. lstead@montefiore.org
authors.forename: Lesley A
authors.initials: LA
authors.lastname: Stead
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Lash
authors.forename: Jerome E
authors.initials: JE
authors.lastname: Sobieraj
authors.forename: Dorcas D
authors.initials: DD
authors.lastname: Chi
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Westrup
authors.forename: Marjory
authors.initials: M
authors.lastname: Charlot
authors.forename: Rita A
authors.initials: RA
authors.lastname: Blanchard
authors.forename: John C
authors.initials: JC
authors.lastname: Lee
authors.forename: Thomas C
authors.initials: TC
authors.lastname: King
authors.forename: Carol L
authors.initials: CL
authors.lastname: Rosenberg