title: Aggressive breast cancer in western Kenya has early onset, high proliferation, and immune cell infiltration.
abstract: BACKGROUND
  Breast cancer incidence and mortality vary significantly among different nations and racial groups. African nations have the highest breast cancer mortality rates in the world, even though the incidence rates are below those of many nations. Differences in disease progression suggest that aggressive breast tumors may harbor a unique molecular signature to promote disease progression. However, few studies have investigated the pathology and clinical markers expressed in breast tissue from regional African patient populations.
  
  
  METHODS
  We collected 68 malignant and 89 non-cancerous samples from Kenyan breast tissue. To characterize the tumors from these patients, we constructed tissue microarrays (TMAs) from these tissues. Sections from these TMAs were stained and analyzed using immunohistochemistry to detect clinical breast cancer markers, including estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor 2 receptor (HER2) status, Ki67, and immune cell markers.
  
  
  RESULTS
  Thirty-three percent of the tumors were triple negative (ER-, PR-, HER2-), 59% were ER+, and almost all tumors analyzed were HER2-. Seven percent of the breast cancer patients were male, and 30% were <40 years old at diagnosis. Cancer tissue had increased immune cell infiltration with recruitment of CD163+ (M2 macrophage), CD25+ (regulatory T lymphocyte), and CD4+ (T helper) cells compared to non-cancer tissue.
  
  
  CONCLUSIONS
  We identified clinical biomarkers that may assist in identifying therapy strategies for breast cancer patients in western Kenya. Estrogen receptor status in particular should lead initial treatment strategies in these breast cancer patients. Increased CD25 expression suggests a need for additional treatment strategies designed to overcome immune suppression by CD25+ cells in order to promote the antitumor activity of CD8+ cytotoxic T cells.
authors.affiliation: University of Notre Dame, Notre Dame, IN, USA.|Harper Cancer Research Institute, University of Notre Dame, 1234 N Notre Dame Avenue, South Bend, IN, USA.|Moi University, Eldoret, Kenya.|Maseno University, Maseno, Kenya.
authors.forename: Rispah T
authors.initials: RT
authors.lastname: Sawe
authors.affiliation: University of Notre Dame, Notre Dame, IN, USA.|Harper Cancer Research Institute, University of Notre Dame, 1234 N Notre Dame Avenue, South Bend, IN, USA.
authors.forename: Maggie
authors.initials: M
authors.lastname: Kerper
authors.affiliation: Harper Cancer Research Institute, University of Notre Dame, 1234 N Notre Dame Avenue, South Bend, IN, USA.|Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: Sunil
authors.initials: S
authors.lastname: Badve
authors.affiliation: University of Notre Dame, Notre Dame, IN, USA.|Harper Cancer Research Institute, University of Notre Dame, 1234 N Notre Dame Avenue, South Bend, IN, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.affiliation: University of Notre Dame, Notre Dame, IN, USA.|Harper Cancer Research Institute, University of Notre Dame, 1234 N Notre Dame Avenue, South Bend, IN, USA.
authors.forename: Mayra
authors.initials: M
authors.lastname: Sandoval-Cooper
authors.affiliation: University of Notre Dame, Notre Dame, IN, USA.|Harper Cancer Research Institute, University of Notre Dame, 1234 N Notre Dame Avenue, South Bend, IN, USA.|Eck Institute for Global Health, Notre Dame, IN, USA.
authors.forename: Jingmeng
authors.initials: J
authors.lastname: Xie
authors.affiliation: Harper Cancer Research Institute, University of Notre Dame, 1234 N Notre Dame Avenue, South Bend, IN, USA.
authors.forename: Zonggao
authors.initials: Z
authors.lastname: Shi
authors.affiliation: Moi University, Eldoret, Kenya.
authors.forename: Kirtika
authors.initials: K
authors.lastname: Patel
authors.affiliation: Moi University, Eldoret, Kenya.
authors.forename: David
authors.initials: D
authors.lastname: Chumba
authors.affiliation: Maseno University, Maseno, Kenya.
authors.forename: Ayub
authors.initials: A
authors.lastname: Ofulla
authors.affiliation: University of Notre Dame, Notre Dame, IN, USA.|Harper Cancer Research Institute, University of Notre Dame, 1234 N Notre Dame Avenue, South Bend, IN, USA.|Indiana University School of Medicine, Indianapolis, IN, USA.|Indiana University School of Medicine-South Bend, South Bend, IN, USA.
authors.forename: Jenifer
authors.initials: J
authors.lastname: Prosperi
authors.affiliation: University of Notre Dame, Notre Dame, IN, USA.|Eck Institute for Global Health, Notre Dame, IN, USA.
authors.forename: Katherine
authors.initials: K
authors.lastname: Taylor
authors.affiliation: University of Notre Dame, Notre Dame, IN, USA.|Harper Cancer Research Institute, University of Notre Dame, 1234 N Notre Dame Avenue, South Bend, IN, USA.|Indiana University School of Medicine, Indianapolis, IN, USA.
authors.forename: M Sharon
authors.initials: MS
authors.lastname: Stack
authors.affiliation: Moi University, Eldoret, Kenya.
authors.forename: Simeon
authors.initials: S
authors.lastname: Mining
authors.affiliation: University of Notre Dame, Notre Dame, IN, USA. laurie.littlepage@nd.edu.|Harper Cancer Research Institute, University of Notre Dame, 1234 N Notre Dame Avenue, South Bend, IN, USA. laurie.littlepage@nd.edu.|Indiana University School of Medicine, Indianapolis, IN, USA. laurie.littlepage@nd.edu.
authors.forename: Laurie E
authors.initials: LE
authors.lastname: Littlepage
mesh_terms: D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics*; D044383:Black People / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007630:Kenya; D008875:Middle Aged; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics; D011960:Receptors, Estrogen / Q000235:genetics; D011980:Receptors, Progesterone / Q000235:genetics; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D046888:Tissue Array Analysis; D064726:Triple Negative Breast Neoplasms / Q000453:epidemiology* / Q000235:genetics / Q000473:pathology*
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human
keywords: Breast cancer; CD163; CD25; Estrogen receptor; Kenya