title: Erythropoietin receptor is expressed in meningiomas and lower levels are associated with tumour recurrence.
abstract: OBJECTIVE
  The Epo-EpoR pathway plays a role in tumour growth, metastasis and treatment resistance and is a potential target in oncological treatment. As the EpoR status in human meningiomas is unknown, our aim was to characterize EpoR expression in these tumours.
  
  
  METHODS
  We examined 131 meningioma samples of all WHO grades from 116 patients by immunohistochemistry for EpoR. Among these, 25 meningiomas showed brain invasion and 29 patients had a further tumour recurrence. A group of 20 patients without tumour recurrence served as controls. In 12 cases we were able to compare both the primary and the following recurrent tumours. The presence of EpoR in meningiomas was confirmed by RT-PCR and Western blot.
  
  
  RESULTS
  EpoR was expressed in all meningiomas. Statistical analysis revealed that the mean expression levels of EpoR were significantly lower in primary tumours with known recurrence compared with a recurrence-free control group. Additional matched pair analysis in individual cases showed no significant differences between primary and recurrent tumours. No significant correlation between EpoR expression and WHO grade, age, sex or brain invasion was detected. Using specific primer pairs for RT-PCR, we were able to detect all three known isoforms of EpoR: the full-length isoform EpoR-F, the truncated isoform EpoR-T and the soluble isoform EpoR-S.
  
  
  CONCLUSIONS
  Our results demonstrate the expression of EpoR in meningiomas. Lower EpoR mean levels might be a useful marker for a higher recurrence risk, but further studies are needed to clarify the influence of EpoR on recurrences and the role of the different isoforms.
authors.affiliation: Institute of Brain Research, University of Tübingen, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Küster
authors.forename: P
authors.initials: P
authors.lastname: Simon
authors.forename: M
authors.initials: M
authors.lastname: Mittelbronn
authors.forename: G
authors.initials: G
authors.lastname: Tabatabai
authors.forename: C
authors.initials: C
authors.lastname: Hermann
authors.forename: H
authors.initials: H
authors.lastname: Strik
authors.forename: K
authors.initials: K
authors.lastname: Dietz
authors.forename: F
authors.initials: F
authors.lastname: Roser
authors.forename: R
authors.initials: R
authors.lastname: Meyermann
authors.forename: J
authors.initials: J
authors.lastname: Schittenhelm
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000175:diagnosis / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000378:metabolism; D008297:Male; D008579:Meningioma / Q000175:diagnosis / Q000378:metabolism*; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000175:diagnosis / Q000378:metabolism*; D009367:Neoplasm Staging; D011379:Prognosis; D020033:Protein Isoforms / Q000378:metabolism; D017467:Receptors, Erythropoietin / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012737:Sex Factors
chemical_list: D019394:Ki-67 Antigen; D020033:Protein Isoforms; D017467:Receptors, Erythropoietin; D011980:Receptors, Progesterone