Apoptosis resistance in pigmented villonodular synovitis

• Autores: Irina Berger, S. Aulmann, V. Ehemann, B. Helmchen, H. Weckauf
• Localización: Histology and histopathology: cellular and molecular biology, ISSN-e 1699-5848, ISSN 0213-3911, Vol. 20, Nº. 1, 2005, págs. 11-17
• Idioma: inglés
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  • Summary. Objective: 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. Methods: 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. Results: 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). Conclusion: 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.