Histology and histopathology Vol.20, nº 1 (2005)

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Browsing Histology and histopathology Vol.20, nº 1 (2005) by Subject "Apoptosis resistance"

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    Apoptosis resistance in pigmented villonodular synovitis
    (Murcia : F. Hernández, 2005) Berger, I.; Aulmann, S.; Ehemann, V.; Helmchen, B.; Weckauf, H.
    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 multiparametric 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.