title: Core needle biopsy of breast cancer tumors increases distant metastases in a mouse model.
abstract: BACKGROUND
  Incisional biopsies, including the diagnostic core needle biopsy (CNB), routinely performed before surgical excision of breast cancer tumors are hypothesized to increase the risk of metastatic disease. In this study, we experimentally determined whether CNB of breast cancer tumors results in increased distant metastases and examine important resultant changes in the primary tumor and tumor microenvironment associated with this outcome.
  
  
  METHODS
  To evaluate the effect of CNB on metastasis development, we implanted murine mammary 4T1 tumor cells in BALB/c mice and performed CNB on palpable tumors in half the mice. Subsequently, emulating the human scenario, all mice underwent complete tumor excision and were allowed to recover, with attendant metastasis development. Tumor growth, lung metastasis, circulating tumor cell (CTC) levels, variation in gene expression, composition of the tumor microenvironment, and changes in immunologic markers were compared in biopsied and non-biopsied mice.
  
  
  RESULTS
  Mice with biopsied tumors developed significantly more lung metastases compared to non-biopsied mice. Tumors from biopsied mice contained a higher frequency of myeloid-derived suppressor cells (MDSCs) accompanied by reduced CD4 + T cells, CD8 + T cells, and macrophages, suggesting biopsy-mediated development of an increasingly immunosuppressive tumor microenvironment. We also observed a CNB-dependent up-regulation in the expression of SOX4, Ezh2, and other key epithelial-mesenchymal transition (EMT) genes, as well as increased CTC levels among the biopsy group.
  
  
  CONCLUSIONS
  CNB creates an immunosuppressive tumor microenvironment, increases EMT, and facilitates release of CTCs, all of which likely contribute to the observed increase in development of distant metastases.
authors.affiliation: Department of Surgery, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada ; Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Edward Gitau
authors.initials: EG
authors.lastname: Mathenge
authors.affiliation: Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada ; Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Cheryl Ann
authors.initials: CA
authors.lastname: Dean
authors.affiliation: Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Derek
authors.initials: D
authors.lastname: Clements
authors.affiliation: Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Vaghar-Kashani
authors.affiliation: Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Steffany
authors.initials: S
authors.lastname: Photopoulos
authors.affiliation: Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Krysta Mila
authors.initials: KM
authors.lastname: Coyle
authors.affiliation: Department of Biology, Saint Francis Xavier University, Antigonish, Nova Scotia, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Giacomantonio
authors.affiliation: Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Malueth
authors.affiliation: Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Anna
authors.initials: A
authors.lastname: Nunokawa
authors.affiliation: Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Julie
authors.initials: J
authors.lastname: Jordan
authors.affiliation: Department of Oncology, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: John D
authors.initials: JD
authors.lastname: Lewis
authors.affiliation: Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada ; Strategy and Organizational Performance, IWK Health Center, Halifax, Nova Scotia, Canada.
authors.forename: Shashi Ashok
authors.initials: SA
authors.lastname: Gujar
authors.affiliation: Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada ; Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Paola
authors.initials: P
authors.lastname: Marcato
authors.affiliation: Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada ; Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Patrick W K
authors.initials: PW
authors.lastname: Lee
authors.affiliation: Department of Surgery, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada ; Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, Nova Scotia, Canada.
authors.forename: Carman Anthony
authors.initials: CA
authors.lastname: Giacomantonio
mesh_terms: D000818:Animals; D062005:Biopsy, Large-Core Needle; D001940:Breast / Q000378:metabolism / Q000473:pathology; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D045744:Cell Line, Tumor; D016207:Cytokines / Q000235:genetics; D004195:Disease Models, Animal; D000071221:Enhancer of Zeste Homolog 2 Protein; D058750:Epithelial-Mesenchymal Transition / Q000235:genetics; D005260:Female; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000556:secondary*; D008214:Lymphocytes / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000378:metabolism / Q000473:pathology*; D008325:Mammary Neoplasms, Experimental / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D008807:Mice, Inbred BALB C; D009360:Neoplastic Cells, Circulating / Q000378:metabolism; D063151:Polycomb Repressive Complex 2 / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055751:SOXC Transcription Factors / Q000235:genetics; D059016:Tumor Microenvironment / Q000235:genetics
chemical_list: D016207:Cytokines; D055751:SOXC Transcription Factors; C489990:Sox4 protein, mouse; D000071221:Enhancer of Zeste Homolog 2 Protein; C498410:Ezh2 protein, mouse; D063151:Polycomb Repressive Complex 2
keywords: CCAC, Canadian Council on Animal Care; CNB, core needle biopsy; CTCs, circulating tumor cells; EMT, epithelial-mesenchymal transition; H&E, hematoxylin and eosin; MDSCs, myeloid-derived suppressor cells; PGE2, prostaglandin E2; breast cancer; core needle biopsy; epithelial-mesenchymal transition; metastasis immunosuppression