title: YKL-40 is a differential diagnostic marker for histologic subtypes of high-grade gliomas.
abstract: OBJECTIVE
  In modern neuro-oncology, no variable affects therapeutic decisions and prognostic estimation more than tumor classification. We showed recently that class prediction models, based on gene expression profiles, classify diagnostically challenging malignant gliomas in a manner that better correlates with clinical outcome than standard pathology. In the present study, we used immunohistochemistry to investigate YKL-40 protein expression in independent sets of glioblastomas and anaplastic oligodendrogliomas to determine whether this single marker can aid classification of these high-grade gliomas.
  
  
  CONCLUSIONS
  Glioblastomas show strikingly more YKL-40 expression than anaplastic oligodendrogliomas. Only 2 of 37 glioblastomas showed completely negative YKL-40 staining in both tumor cells and extracellular matrix, whereas 18 of 29 anaplastic oligodendrogliomas were completely negative in non-microgemistocytic tumor cells and extracellular matrix. Tumor cell staining intensity was also markedly different: 84% of glioblastomas showed strong staining intensities of 2+ or 3+ whereas 76% of anaplastic oligodendrogliomas either did not stain or stained at only 1+. YKL-40 staining provided a better class distinction of glioblastoma versus anaplastic oligodendroglioma than glial fibrillary acidic protein, the current standard immunohistochemical marker used to distinguish diagnostically challenging gliomas. Moreover, a combination of YKL-40 and glial fibrillary acidic protein immunohistochemistry afforded even greater diagnostic accuracy in anaplastic oligodendrogliomas.
authors.affiliation: Molecular Neuro-Oncology Laboratory and Molecular Pathology Unit, Department of Pathology, Massachusetts General Hospital, 149 13th Street, Charlestown, MA 02129, USA.
authors.forename: Catherine L
authors.initials: CL
authors.lastname: Nutt
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Betensky
authors.forename: Melissa A
authors.initials: MA
authors.lastname: Brower
authors.forename: Tracy T
authors.initials: TT
authors.lastname: Batchelor
authors.forename: David N
authors.initials: DN
authors.lastname: Louis
authors.forename: Anat O
authors.initials: AO
authors.lastname: Stemmer-Rachamimov
mesh_terms: D054392:Adipokines; D001324:Autoantigens / Q000378:metabolism; D014408:Biomarkers, Tumor / Q000378:metabolism*; D001932:Brain Neoplasms / Q000175:diagnosis / Q000378:metabolism; D000071451:Chitinase-3-Like Protein 1; D003937:Diagnosis, Differential; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D005909:Glioblastoma / Q000175:diagnosis* / Q000378:metabolism*; D006023:Glycoproteins / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D037102:Lectins; D009367:Neoplasm Staging; D009837:Oligodendroglioma / Q000175:diagnosis* / Q000378:metabolism*; D011379:Prognosis
chemical_list: D054392:Adipokines; D001324:Autoantigens; D014408:Biomarkers, Tumor; C084533:CHI3L1 protein, human; D000071451:Chitinase-3-Like Protein 1; D005904:Glial Fibrillary Acidic Protein; D006023:Glycoproteins; D037102:Lectins