title: Heterogeneity of chemokine cell-surface receptor expression in triple-negative breast cancer.
abstract: BACKGROUND
  Tumor heterogeneity is a well-established concept in cancer research. In this paper, we examine an additional type of tumor cell heterogeneity - tumor cell-surface receptor heterogeneity.
  
  
  METHODS
  We use flow cytometry to measure the frequency and numbers of cell-surface receptors on triple negative breast cancer cell lines.
  
  
  RESULTS
  We find two distinct populations of human triple-negative breast cancer cells MDA-MB-231 when they are grown in culture, one with low surface levels of various chemokine receptors and a second with much higher levels. The population with high surface levels of these receptors is increased in the more metastatic MDA-MB-231-luc-d3h2ln cell line.
  
  
  CONCLUSIONS
  We hypothesize that this high cell-surface receptor population is involved in metastasis. We find that the receptor high populations can be modulated by tumor conditioned media and IL6 treatment indicating that the tumor microenvironment is important for the maintenance and sizes of these populations.
authors.affiliation: Department of Biomedical Engineering, School of Medicine, Johns Hopkins University Baltimore, MD 21205, USA.
authors.forename: Kerri-Ann
authors.initials: KA
authors.lastname: Norton
authors.affiliation: Department of Biomedical Engineering, School of Medicine, Johns Hopkins University Baltimore, MD 21205, USA ; Department of Oncology and The Sidney Kimmel Comprehensive Cancer Center, School of Medicine, Johns Hopkins University Baltimore, MD, USA.
authors.forename: Aleksander S
authors.initials: AS
authors.lastname: Popel
authors.affiliation: Department of Biomedical Engineering, School of Medicine, Johns Hopkins University Baltimore, MD 21205, USA.
authors.forename: Niranjan B
authors.initials: NB
authors.lastname: Pandey
keywords: CCR5; CXCR3; CXCR4; IL6; MDA-MB-231; stem cells