title: Population differences in breast cancer: survey in indigenous African women reveals over-representation of triple-negative breast cancer.
abstract: OBJECTIVE
  Compared with white women, black women experience a disproportionate burden of aggressive breast cancer for reasons that remain unknown and understudied. In the first study of its kind, we determined the distribution of molecular subtypes of invasive breast tumors in indigenous black women in West Africa.
  
  
  METHODS
  The study comprised 507 patients diagnosed with breast cancer between 1996 and 2007 at six geographic regions in Nigeria and Senegal. Formalin-fixed and paraffin-embedded sections were constructed into tissue microarrays and immunostained with 15 antibodies. Five molecular subtypes were determined, and hierarchical cluster analysis was conducted to explore subgroups for unclassified cases.
  
  
  RESULTS
  The mean (+/- standard deviation) age of 378 patients in the first cohort was 44.8 +/- 11.8 years, with the majority of women presenting with large (4.4 +/- 2.0 cm) high-grade tumors (83%) in advanced stages (72% node positive). The proportions of estrogen receptor (ER) -positive, progesterone receptor-positive, and human epidermal growth factor receptor 2 (HER2) -positive tumors were 24%, 20%, and 17%, respectively. Triple negativity for these markers was predominant, including basal-like (27%) and unclassified subtype (28%). Other subtypes were luminal A (27%), luminal B (2%), and HER2 positive/ER negative (15%). The findings were replicated in the second cohort of 129 patients. The unclassified cases could be grouped into a bad prognosis branch, with expression of vascular endothelial growth factor, B-cell lymphoma extra-large protein, and Cyclin E, and a good prognosis branch, with expression of B-cell lymphoma protein 2 and Cyclin D1.
  
  
  CONCLUSIONS
  These findings underscore the urgent need for research into the etiology and treatment of the aggressive molecular subtypes that disproportionately affect young women in the African diaspora.
authors.affiliation: Center for Clinical Cancer Genetics and Global Health, Department of Medicine, Section of Hematology/Oncology, University of Chicago, 5841 S Maryland Ave, MC 2115, Chicago, IL 60637, USA.
authors.forename: Dezheng
authors.initials: D
authors.lastname: Huo
authors.forename: Francis
authors.initials: F
authors.lastname: Ikpatt
authors.forename: Andrey
authors.initials: A
authors.lastname: Khramtsov
authors.forename: Jean-Marie
authors.initials: JM
authors.lastname: Dangou
authors.forename: Rita
authors.initials: R
authors.lastname: Nanda
authors.forename: James
authors.initials: J
authors.lastname: Dignam
authors.forename: Bifeng
authors.initials: B
authors.lastname: Zhang
authors.forename: Tatyana
authors.initials: T
authors.lastname: Grushko
authors.forename: Chunling
authors.initials: C
authors.lastname: Zhang
authors.forename: Olayiwola
authors.initials: O
authors.lastname: Oluwasola
authors.forename: David
authors.initials: D
authors.lastname: Malaka
authors.forename: Sani
authors.initials: S
authors.lastname: Malami
authors.forename: Abayomi
authors.initials: A
authors.lastname: Odetunde
authors.forename: Adewumi O
authors.initials: AO
authors.lastname: Adeoye
authors.forename: Festus
authors.initials: F
authors.lastname: Iyare
authors.forename: Adeyinka
authors.initials: A
authors.lastname: Falusi
authors.forename: Charles M
authors.initials: CM
authors.lastname: Perou
authors.forename: Olufunmilayo I
authors.initials: OI
authors.lastname: Olopade
mesh_terms: D000328:Adult; D014408:Biomarkers, Tumor / Q000097:blood*; D001943:Breast Neoplasms / Q000453:epidemiology* / Q000378:metabolism*; D015331:Cohort Studies; D005260:Female; D018734:Genes, erbB-2; D006306:Health Surveys; D006801:Humans; D008875:Middle Aged; D009549:Nigeria / Q000453:epidemiology; D011960:Receptors, Estrogen / Q000097:blood*; D011980:Receptors, Progesterone / Q000097:blood*; D012675:Senegal / Q000453:epidemiology
chemical_list: D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone
references.citation: Breast Cancer Res Treat. 2008 Jul;110(1):183-8
references.pmid: 17674190
references.citation: N Engl J Med. 2006 Aug 10;355(6):560-9
references.pmid: 16899776
references.citation: Mod Pathol. 2006 Feb;19(2):264-71
references.pmid: 16341146
references.citation: Cancer. 2007 May 1;109(9):1721-8
references.pmid: 17387718
references.citation: Clin Cancer Res. 2004 Aug 15;10(16):5367-74
references.pmid: 15328174
references.citation: Breast. 2007 Dec;16 Suppl 2:S72-7
references.pmid: 17714947
references.citation: West Afr J Med. 2005 Jul-Sep;24(3):209-13
references.pmid: 16276696
references.citation: J Clin Oncol. 2006 May 10;24(14):2137-50
references.pmid: 16682732
references.citation: Cancer Res. 1990 Nov 1;50(21):7057-61
references.pmid: 2208173
references.citation: Br J Surg. 1999 May;86(5):665-8
references.pmid: 10361191
references.citation: Br J Surg. 1992 Aug;79(8):771-5
references.pmid: 1393468
references.citation: Proc Natl Acad Sci U S A. 1998 Dec 8;95(25):14863-8
references.pmid: 9843981
references.citation: Cancer Epidemiol Biomarkers Prev. 2007 Mar;16(3):439-43
references.pmid: 17372238
references.citation: Histopathology. 1991 Nov;19(5):403-10
references.pmid: 1757079
references.citation: J Natl Cancer Inst. 2005 Mar 16;97(6):439-48
references.pmid: 15770008
references.citation: CA Cancer J Clin. 2006 May-Jun;56(3):168-83
references.pmid: 16737949
references.citation: Nat Med. 1998 Jul;4(7):844-7
references.pmid: 9662379
references.citation: Breast Cancer Res Treat. 2008 May;109(1):123-39
references.pmid: 17578664
references.citation: Cent Afr J Med. 2003 Nov-Dec;49(11-12):122-6
references.pmid: 15301464
references.citation: Nature. 2000 Aug 17;406(6797):747-52
references.pmid: 10963602
references.citation: Ann Intern Med. 2006 Apr 18;144(8):541-53
references.pmid: 16618951
references.citation: J Surg Res. 2007 Nov;143(1):109-18
references.pmid: 17950079
references.citation: Br J Cancer. 2008 Jan 29;98(2):277-81
references.pmid: 18182985
references.citation: JAMA. 1994 Sep 28;272(12):947-54
references.pmid: 8084062
references.citation: J Clin Oncol. 2006 Mar 20;24(9):1342-9
references.pmid: 16549828
references.citation: Cancer. 2007 Jan 1;109(1):25-32
references.pmid: 17146782
references.citation: JAMA. 2006 Jun 7;295(21):2492-502
references.pmid: 16757721
references.citation: Breast Cancer Res Treat. 2002 Jun;74(3):199-211
references.pmid: 12206512