title: Leukaemia inhibitory factor (LIF) is immunohistochemically expressed in normal, hyperplastic and malignant endometrial tissue.
abstract: OBJECTIVE
  Leukaemia inhibitory factor (LIF) is a pleiotrophic cytokine, which might play an important role in human reproduction and endocrine-responsive tumours. Therefore, the aim of this study was to determine the frequency and tissue distribution of LIF in normal, hyperplastic and malignant endometrium.
  
  
  METHODS
  Paraffin-fixed endometrial tissue was obtained from normal premenopausal women (n = 15), endometrial hyperplasia (n = 20), endometroid adenocarcinoma (n = 32) and endometrial polyps (n = 9). The LIF expression was demonstrated by immunohistochemical means and evaluated with a semi-quantitative immunoreactive score. The Mann-Whitney U-test was used for statistical evaluation.
  
  
  RESULTS
  The lowest expression of LIF was observed in endometrial adenocarcinomas compared to all groups, while endometrial polyps expressed the highest LIF immunostaining. The expression in normal human glandular cells was significantly higher during the late secretory phase than in the proliferative phase. The highest expression of LIF was observed in endometrial polyps. Simple hyperplasia showed a significantly higher LIF expression than proliferative endometrium and adenocarcinoma. Adenomatous hyperplasia (AH) grade I-III had a significantly higher LIF expression than adenocarcinoma. The lowest expression of LIF was observed in adenocarcinoma, being statistically significant compared to all groups.
  
  
  CONCLUSIONS
  LIF was immunohistochemically demonstrated in normal, hyperplastic and malignant endometrial tissue, suggesting a widespread but complex role for LIF in hyperplastic and malignant endometrial growth regulation. AH I-III also expressed LIF with statistically higher immunostaining than adenocarcinoma. Since AH III can be considered as a precursor of endometrial cancer, LIF could be a marker of cell transformation.
authors.affiliation: First Department of Obstetrics and Gynaecology, Ludwig-Maximilians-University Munich, Maistrasse 11, 80337 Munich, Germany.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Mylonas
authors.forename: Josef
authors.initials: J
authors.lastname: Makovitzky
authors.forename: Naim
authors.initials: N
authors.lastname: Shabani
authors.forename: Dagmar-Ulrike
authors.initials: DU
authors.lastname: Richter
authors.forename: Christina
authors.initials: C
authors.lastname: Kuhn
authors.forename: Udo
authors.initials: U
authors.lastname: Jeschke
authors.forename: Volker
authors.initials: V
authors.lastname: Briese
authors.forename: Klaus
authors.initials: K
authors.lastname: Friese
mesh_terms: D000230:Adenocarcinoma / Q000737:chemistry; D004714:Endometrial Hyperplasia / Q000378:metabolism*; D016889:Endometrial Neoplasms / Q000737:chemistry*; D004717:Endometrium / Q000737:chemistry*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D015850:Interleukin-6 / Q000032:analysis*; D053605:Leukemia Inhibitory Factor; D011127:Polyps / Q000737:chemistry; D017697:Premenopause
chemical_list: D015850:Interleukin-6; C507837:LIF protein, human; D053605:Leukemia Inhibitory Factor