title: Immunohistochemical study of MRP5 expression in meningiomas.
abstract: OBJECTIVE
  Meningiomas are the most common benign intracranial tumor, accounting for 30% of all primary intracranial tumors. Although benign meningiomas rarely recur after a complete resection, anaplastic tumors are associated with high recurrence rate and unfavorable outcome. In the current study, we investigated the expression of the multidrug resistance protein 5 (MRP5) in patients with meningiomas.
  
  
  METHODS
  We retrospectively studied twenty patients with meningiomas that were treated surgically in our institute over a 3-year period. MRP5 protein expression was determined immunohistochemically.
  
  
  RESULTS
  The immunohistochemical expression of MRP5 was observed only in anaplastic meningiomas. No MRP5 expression was detected in benign or atypical meningiomas. No significant correlation was found between MRP5 expression and Ki-67 index. After a mean follow-up period of 23 months, there were 4 cases of tumor recurrence. No correlation was found between extent of resection and tumor recurrence.
  
  
  CONCLUSIONS
  Immunohistochemical MRP5 protein expression was observed only in anaplastic meningiomas. Further research is needed to clarify whether MRP5 is indicative of malignant pathological features in meningiomas and whether possible therapeutic implications exist.
authors.affiliation: Department of Neurosurgery, University Hospital of Ioannina, Neohoropoulo, PO Box 103, 45500 Ioannina, Greece. alexiougrg@yahoo.gr
authors.forename: George A
authors.initials: GA
authors.lastname: Alexiou
authors.forename: Ann
authors.initials: A
authors.lastname: Goussia
authors.forename: Antigoni
authors.initials: A
authors.lastname: Ntoulia
authors.forename: Panagiota
authors.initials: P
authors.lastname: Zagorianakou
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Malamou-Mitsi
authors.forename: Spyridon
authors.initials: S
authors.lastname: Voulgaris
authors.forename: Athanasios P
authors.initials: AP
authors.lastname: Kyritsis
mesh_terms: D000368:Aged; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D019008:Drug Resistance, Neoplasm / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D008577:Meningeal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008579:Meningioma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D008875:Middle Aged; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000096:biosynthesis* / Q000235:genetics; D009364:Neoplasm Recurrence, Local; D012189:Retrospective Studies; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D019394:Ki-67 Antigen; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D014157:Transcription Factors; C120809:ABCC5 protein, human; C077171:HIVEP2 protein, human