title: Specific visualization of glioma cells in living low-grade tumor tissue.
abstract: BACKGROUND
  The current therapy of malignant gliomas is based on surgical resection, radio-chemotherapy and chemotherapy. Recent retrospective case-series have highlighted the significance of the extent of resection as a prognostic factor predicting the course of the disease. Complete resection in low-grade gliomas that show no MRI-enhanced images are especially difficult. The aim in this study was to develop a robust, specific, new fluorescent probe for glioma cells that is easy to apply to live tumor biopsies and could identify tumor cells from normal brain cells at all levels of magnification.
  
  
  RESULTS
  In this investigation we employed brightly fluorescent, photostable quantum dots (QDs) to specifically target epidermal growth factor receptor (EGFR) that is upregulated in many gliomas. Living glioma and normal cells or tissue biopsies were incubated with QDs coupled to EGF and/or monoclonal antibodies against EGFR for 30 minutes, washed and imaged. The data include results from cell-culture, animal model and ex vivo human tumor biopsies of both low-grade and high-grade gliomas and show high probe specificity. Tumor cells could be visualized from the macroscopic to single cell level with contrast ratios as high as 1000: 1 compared to normal brain tissue.
  
  
  CONCLUSIONS
  The ability of the targeted probes to clearly distinguish tumor cells in low-grade tumor biopsies, where no enhanced MRI image was obtained, demonstrates the great potential of the method. We propose that future application of specifically targeted fluorescent particles during surgery could allow intraoperative guidance for the removal of residual tumor cells from the resection cavity and thus increase patient survival.
authors.affiliation: Department of Neurosurgery, Georg-August-University of Göttingen, Göttingen, Germany.
authors.forename: Sven R
authors.initials: SR
authors.lastname: Kantelhardt
authors.forename: Wouter
authors.initials: W
authors.lastname: Caarls
authors.forename: Anthony H B
authors.initials: AH
authors.lastname: de Vries
authors.forename: Guy M
authors.initials: GM
authors.lastname: Hagen
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Jovin
authors.forename: Walter
authors.initials: W
authors.lastname: Schulz-Schaeffer
authors.forename: Veit
authors.initials: V
authors.lastname: Rohde
authors.forename: Alf
authors.initials: A
authors.lastname: Giese
authors.forename: Donna J
authors.initials: DJ
authors.lastname: Arndt-Jovin
mesh_terms: D000818:Animals; D001706:Biopsy; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology*; D066246:ErbB Receptors / Q000378:metabolism; D005909:Glioblastoma / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D051379:Mice; D009368:Neoplasm Transplantation; D045663:Quantum Dots
chemical_list: D066246:ErbB Receptors