title: Apoptosis resistance in pigmented villonodular synovitis.
abstract: Pigmented villonodular synovitis (PVNS) is a proliferative lesion originating from synovial tissue with a locally aggressive behaviour. We analysed the pathogenetic role of apoptosis resistance for sustained cell proliferation in PVNS.
  
  
  
  The expression of bcl-2, p53 and Ki-67 was examined in 80 cases of PVNS using immunohistochemistry. In 43 of these cases, DNA content and distribution of cell-cycle phases were investigated by flow cytometry. Additionally, 10 cases of PVNS were analysed by multi-parametric flow cytometry for expression of p53, caspase3, and bcl-2 and by TUNEL to detect DNA fragmentation.
  
  
  
  No apoptotic cell fractions were detected in any investigated cases. Expression of bcl-2 was found in 84% of cases (up to 6.5% of cells) and was significantly associated with DNA-fragmentation observed by TUNEL (p=0.037). Orthologous p53 expression was observed in 37% of cases. The level of p53 expression correlated with the proliferative activity and the expression of both caspase3 (p=0.017) and bcl-2 (p=0.0013). (No statistically significant correlations between expression of bcl-2, p53, caspase3, DNA fragmentation or proliferative index and age, sex of patients, disease recurrence, growth pattern or size of lesion were found).
  
  
  
  Apoptosis resistance is a critical event in the progression of PVNS and may contribute to the survival of the proliferating synovial cells in PVNS and to the permanent slow progression of these lesions.
authors.affiliation: Institute of Pathology, University of Heidelberg, 69120 Heidelberg, Germany. Irina_Berger@med.uni-heidelberg.de
authors.forename: I
authors.initials: I
authors.lastname: Berger
authors.forename: S
authors.initials: S
authors.lastname: Aulmann
authors.forename: V
authors.initials: V
authors.lastname: Ehemann
authors.forename: B
authors.initials: B
authors.lastname: Helmchen
authors.forename: H
authors.initials: H
authors.lastname: Weckauf
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017209:Apoptosis / Q000502:physiology*; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D013586:Synovitis, Pigmented Villonodular / Q000473:pathology* / Q000503:physiopathology