title: Local iron homeostasis in the breast ductal carcinoma microenvironment.
abstract: BACKGROUND
  While the deregulation of iron homeostasis in breast epithelial cells is acknowledged, iron-related alterations in stromal inflammatory cells from the tumor microenvironment have not been explored.
  
  
  METHODS
  Immunohistochemistry for hepcidin, ferroportin 1 (FPN1), transferrin receptor 1 (TFR1) and ferritin (FT) was performed in primary breast tissues and axillary lymph nodes in order to dissect the iron-profiles of epithelial cells, lymphocytes and macrophages. Furthermore, breast carcinoma core biopsies frozen in optimum cutting temperature (OCT) compound were subjected to imaging flow cytometry to confirm FPN1 expression in the cell types previously evaluated and determine its cellular localization.
  
  
  RESULTS
  We confirm previous results by showing that breast cancer epithelial cells present an 'iron-utilization phenotype' with an increased expression of hepcidin and TFR1, and decreased expression of FT. On the other hand, lymphocytes and macrophages infiltrating primary tumors and from metastized lymph nodes display an 'iron-donor' phenotype, with increased expression of FPN1 and FT, concomitant with an activation profile reflected by a higher expression of TFR1 and hepcidin. A higher percentage of breast carcinomas, compared to control mastectomy samples, present iron accumulation in stromal inflammatory cells, suggesting that these cells may constitute an effective tissue iron reservoir. Additionally, not only the deregulated expression of iron-related proteins in epithelial cells, but also on lymphocytes and macrophages, are associated with clinicopathological markers of breast cancer poor prognosis, such as negative hormone receptor status and tumor size.
  
  
  CONCLUSIONS
  The present results reinforce the importance of analyzing the tumor microenvironment in breast cancer, extending the contribution of immune cells to local iron homeostasis in the tumor microenvironment context.
authors.affiliation: Laboratory of Immunogenetics - Autoimmunity and Neurosciences, Unit for Multidisciplinary Biomedical Research (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Rua Jorge Viterbo Ferreira 228,Edif 2 Piso 4, P-4050313, Porto, Portugal. oamarques@icbas.up.pt.|Pathology and Molecular Immunology Department, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal. oamarques@icbas.up.pt.|Basic and Clinical Research on Iron Biology, Instituto de Biologia Molecular e Celular (IBMC), University of Porto, Porto, Portugal. oamarques@icbas.up.pt.|Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal. oamarques@icbas.up.pt.
authors.forename: Oriana
authors.initials: O
authors.lastname: Marques
authors.affiliation: Pathology and Molecular Immunology Department, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal. gporto@ibmc.up.pt.|Hematology Service, Hospital de Santo António, Centro Hospitalar do Porto, Porto, Portugal. gporto@ibmc.up.pt.
authors.forename: Graça
authors.initials: G
authors.lastname: Porto
authors.affiliation: Pathology and Molecular Immunology Department, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal. alexandra.rema@gmail.com.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Rêma
authors.affiliation: Pathology and Molecular Immunology Department, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal. fatimafaria10@yahoo.com.br.
authors.forename: Fátima
authors.initials: F
authors.lastname: Faria
authors.affiliation: Pathology and Molecular Immunology Department, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal. arnaudcpaula@hotmail.com.|Department of Pathology, Portuguese Oncology Institute (IPO), Porto, Portugal. arnaudcpaula@hotmail.com.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Cruz Paula
authors.affiliation: Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal. Maria.GLazaro@ineb.up.pt.|Instituto Nacional de Engenharia Biomédica (INEB), University of Porto, Porto, Portugal. Maria.GLazaro@ineb.up.pt.
authors.forename: Maria
authors.initials: M
authors.lastname: Gomez-Lazaro
authors.affiliation: Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal. psilva@ipatimup.pt.|Faculty of Medicine of University of Porto (FMUP), Porto, Portugal. psilva@ipatimup.pt.|Institute of Molecular Pathology and Immunology, University of Porto, Porto, Portugal. psilva@ipatimup.pt.
authors.forename: Paula
authors.initials: P
authors.lastname: Silva
authors.affiliation: Laboratory of Immunogenetics - Autoimmunity and Neurosciences, Unit for Multidisciplinary Biomedical Research (UMIB), Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Rua Jorge Viterbo Ferreira 228,Edif 2 Piso 4, P-4050313, Porto, Portugal. bertams@icbas.up.pt.|Pathology and Molecular Immunology Department, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal. bertams@icbas.up.pt.
authors.forename: Berta
authors.initials: B
authors.lastname: Martins da Silva
authors.affiliation: Pathology and Molecular Immunology Department, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal. calopes@icbas.up.pt.|Department of Pathology, Portuguese Oncology Institute (IPO), Porto, Portugal. calopes@icbas.up.pt.
authors.forename: Carlos
authors.initials: C
authors.lastname: Lopes
mesh_terms: D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D015415:Biomarkers; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D015870:Gene Expression; D064451:Hepcidins / Q000235:genetics / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D007150:Immunohistochemistry; D007501:Iron / Q000378:metabolism*; D008198:Lymph Nodes / Q000378:metabolism / Q000473:pathology; D011990:Receptors, Transferrin / Q000235:genetics / Q000378:metabolism; D047368:Tumor Burden; D059016:Tumor Microenvironment; D000098742:Ferroportin
chemical_list: D015703:Antigens, CD; D015415:Biomarkers; C068126:CD71 antigen; D027682:Cation Transport Proteins; D064451:Hepcidins; D011990:Receptors, Transferrin; D000098742:Ferroportin; D007501:Iron