title: The Role of Exosomes in Breast Cancer.
abstract: BACKGROUND
  Although it has been long realized that eukaryotic cells release complex vesicular structures into their environment, only in recent years has it been established that these entities are not merely junk or debris, but that they are tailor-made specialized minimaps of their cell of origin and of both physiological and pathological relevance. These exosomes and microvesicles (ectosomes), collectively termed extracellular vesicles (EVs), are often defined and subgrouped first and foremost according to size and proposed origin (exosomes approximately 30-120 nm, endosomal origin; microvesicles 120-1000 nm, from the cell membrane). There is growing interest in elucidating the relevance and roles of EVs in cancer.
  
  
  BACKGROUND
  Much of the pioneering work on EVs in cancer has focused on breast cancer, possibly because breast cancer is a leading cause of cancer-related deaths worldwide. This review provides an in-depth summary of such studies, supporting key roles for exosomes and other EVs in breast cancer cell invasion and metastasis, stem cell stimulation, apoptosis, immune system modulation, and anti-cancer drug resistance. Exosomes as diagnostic, prognostic, and/or predictive biomarkers and their potential use in the development of therapeutics are discussed.
  
  
  CONCLUSIONS
  Although not fully elucidated, the involvement of exosomes in breast cancer development, progression, and resistance is becoming increasingly apparent from preclinical and clinical studies, with mounting interest in the potential exploitation of these vesicles for breast cancer biomarkers, as drug delivery systems, and in the development of future novel breast cancer therapies.
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences & Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland;
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Lowry
authors.affiliation: School of Biomolecular and Biomedical Science, University College Dublin Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland.
authors.forename: William M
authors.initials: WM
authors.lastname: Gallagher
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences & Trinity Biomedical Sciences Institute, Trinity College Dublin, Dublin 2, Ireland; lodrisc@tcd.ie.
authors.forename: Lorraine
authors.initials: L
authors.lastname: O'Driscoll
mesh_terms: D017209:Apoptosis / Q000235:genetics / Q000276:immunology; D001943:Breast Neoplasms / Q000175:diagnosis / Q000235:genetics / Q000276:immunology / Q000473:pathology*; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism; D055252:Cell-Derived Microparticles / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D055354:Exosomes / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007113:Immunity, Innate; D009362:Neoplasm Metastasis; D009363:Neoplasm Proteins / Q000235:genetics* / Q000276:immunology; D014411:Neoplastic Stem Cells / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D053141:Organelle Size
chemical_list: D009363:Neoplasm Proteins