title: Reduced levels of E-cadherin correlate with progression of corticotroph pituitary tumours.
abstract: OBJECTIVE
  Loss of E-cadherin is an important marker of epithelial tumour progression. The aims of this study were to explore whether E-cadherin expression and localization correlate to corticotroph tumour progression, relate the expression of the E-cadherin gene (CDH1) to immunohistochemical E-cadherin staining pattern, and study whether the E-cadherin levels were correlated to methylation status of the CDH1 promoter region.
  
  
  METHODS
  Immunohistochemical analyses of E-cadherin protein were performed, as was RT-qPCR of the CDH1 and the POMC genes. Methylation pattern of the promoter region of CDH1 was measured using pyrosequencing of bisulfite-treated DNA.
  
  
  METHODS
  Forty-five patients operated at a tertiary referral centre in Oslo, Norway. Adenoma tissue sections and RNA samples from patients with verified Cushing's disease or Nelson's syndrome were collected.
  
  
  METHODS
  Expression of E-cadherin mRNA and protein in pituitary corticotroph adenomas and average percentage of methylated cytosines in a cytosine-phosphate-guanosine island of the CDH1 promoter.
  
  
  RESULTS
  Correlations were observed between tumour progression and both nuclear expression of E-cadherin and reduced CDH1 mRNA. The E-cadherin expression was not determined by the methylation pattern of the CDH1 promoter.
  
  
  CONCLUSIONS
  Corticotroph tumour progression was associated with reduced expression of the epithelial marker E-cadherin.
authors: Section of Specialised Endocrinology, Department of Endocrinology, Oslo University Hospital, Rikshospitalet, Oslo, Norway. j.a.evang@medisin.uio.no
authors: Johan Arild
authors: JA
authors: Evang
authors: Jens Petter
authors: JP
authors: Berg
authors: Olivera
authors: O
authors: Casar-Borota
authors: Tove
authors: T
authors: Lekva
authors: Marianne Kristiansen
authors: MK
authors: Kringen
authors: Jon
authors: J
authors: Ramm-Pettersen
authors: Jens
authors: J
authors: Bollerslev