title: L1 is highly expressed in tumors of the nervous system: a study of over 8000 human tissues.
abstract: BACKGROUND
  L1 cell adhesion molecule (CD171) has been detected in different malignant tumors and is associated with unfavorable outcome. It thus represents a target for tumor diagnosis and therapy. In this study, we assessed L1 expression in more than 8000 normal human tissues and different types of tumors, both malignant and non-malignant, and neural and non-neural.
  
  
  METHODS
  Tissue micro-arrays, including a multi-tumor-array of 128 different tumor types, up to 50 samples of each type (approximately 5500 different samples), arrays with approximately 3000 different prostate and 600 mesenchymal tumor samples, and a normal human tissue-array were analyzed by immunohistochemistry with a monoclonal antibody using immunoperoxidase staining.
  
  
  RESULTS
  L1 expression was detected in tumors of neural and neural crest origin and other types of non-neural tumors, but not in those of epithelial origin. In normal human tissues, L1 was detected in skin basal cells and small blood vessels, most notably in the mature placenta and peripheral nerves.
  
  
  CONCLUSIONS
  This first comprehensive study of the importance of L1 expression in human demonstrates strong L1 overexpression in tumors of neuroectodermal and neural crest origin and an expression in only very few normal human tissues. L1 thus is a potentially important therapeutic target, particularly with respect to malignant melanoma, gastrointestinal stromal tumor, neuroblastoma, and certain subtypes of non-neural tumors.
authors.affiliation: Department of General, Visceral and Thoracic Surgery, University Medical Center, Hamburg-Eppendorf, Hamburg, Germany. trawnaq@uke.de
authors.forename: Tamina
authors.initials: T
authors.lastname: Rawnaq
authors.forename: Alexander
authors.initials: A
authors.lastname: Quaas
authors.forename: Hilke
authors.initials: H
authors.lastname: Zander
authors.forename: Stephanie J
authors.initials: SJ
authors.lastname: Gros
authors.forename: Uta
authors.initials: U
authors.lastname: Reichelt
authors.forename: Marco
authors.initials: M
authors.lastname: Blessmann
authors.forename: Waldemar
authors.initials: W
authors.lastname: Wilzcak
authors.forename: Melitta
authors.initials: M
authors.lastname: Schachner
authors.forename: Guido
authors.initials: G
authors.lastname: Sauter
authors.forename: Jakob R
authors.initials: JR
authors.lastname: Izbicki
authors.forename: Jussuf T
authors.initials: JT
authors.lastname: Kaifi
mesh_terms: D014408:Biomarkers, Tumor / Q000378:metabolism*; D006801:Humans; D009423:Nervous System Neoplasms / Q000378:metabolism*; D039842:Neural Cell Adhesion Molecule L1 / Q000378:metabolism*; D046888:Tissue Array Analysis
chemical_list: D014408:Biomarkers, Tumor; D039842:Neural Cell Adhesion Molecule L1