title: Galectin-3 expression: a useful tool in the differential diagnosis of posterior fossa tumors in children.
abstract: OBJECTIVE
  Galectin-3 (Gal-3) is a glycan-binding protein highly expressed in several tumors, including brain neoplasms. This protein has been demonstrated to be correlated with adverse prognosis in some tumor types. However, the role of Gal-3 in pediatric posterior fossa tumors (PPFTs) has not yet been fully addressed. The goals of this study were to evaluate Gal-3 expression in a series of PPFTs and verify whether this expression is related to patient outcome.
  
  
  METHODS
  Gal-3 expression was analyzed by immunohistochemistry in 42 cases of surgically resected primary PPFTs. Surgeries were performed in our institution from January 2003 to December 2006. Tumor samples consisted of 21 pilocytic astrocytomas (PAs), 13 medulloblastomas, 4 ependymomas, 2 diffuse cerebellar astrocytomas, and 2 atypical teratoid/rhabdoid tumors (AT/RTs).
  
  
  RESULTS
  All PAs and ependymomas strongly showed Gal-3 expression, whereas no immunostaining was observed in medulloblastomas and diffuse astrocytomas. In AT/RTs, Gal-3 expression was conspicuous but heterogeneous, being mainly observed in rhabdoid cells. Concerning the Gal-3 expressing tumors, no relationship was observed between the degree of expression and patient survival. Gal-3 was strongly expressed in reactive astrocytes, normal endothelial cells, and macrophages in the adjacent non-neoplastic brain parenchyma. Interestingly, the endothelial cells in the tumor bulk of PAs lacked Gal-3 expression.
  
  
  CONCLUSIONS
  Gal-3 is differentially expressed in PPFTs, but its expression shows no correlation with patient outcome. However, the evaluation of Gal-3 is helpful in establishing a differential diagnosis among PPFTs, especially between PAs and diffuse astrocytomas, and in some circumstances between medulloblastomas and AT/RTs.
authors: Department of Cell and Molecular Biology and Pathogenic Bioagents, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, Brazil.
authors: Carolina Bisinoto
authors: CB
authors: Borges
authors: Emerson Soares
authors: ES
authors: Bernardes
authors: Elder Francisco
authors: EF
authors: Latorraca
authors: Aline Paixão
authors: AP
authors: Becker
authors: Luciano
authors: L
authors: Neder
authors: Roger
authors: R
authors: Chammas
authors: Maria Cristina
authors: MC
authors: Roque-Barreira
authors: Hélio Rubens
authors: HR
authors: Machado
authors: Ricardo Santos
authors: RS
authors: de Oliveira
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D003937:Diagnosis, Differential; D037502:Galectin 3 / Q000096:biosynthesis*; D006801:Humans; D007150:Immunohistochemistry; D015192:Infratentorial Neoplasms / Q000378:metabolism* / Q000473:pathology; D016133:Polymerase Chain Reaction
chemical_list: D014408:Biomarkers, Tumor; D037502:Galectin 3