bcl-2 is preferentially expressed in tumours of muscle origin but is not related to p53 expression

bcl-2 is a proto-oncogene which inhibits apoptosis. In contrast, p53 tumour suppressor gene is known to induce apoptosis. In this study we analysed immunohistochemically 63 mesenchymal tumours for the expression of bcl-2 and p53 proteins with a special emphasis on muscle-derived tumours. bcl-2 was expressed in all seven rhabdomyosarcomas and in five out of seven leiomyosarcomas. In benign muscle tumours, bcl-2 expression was found in all four epithelioid leiomyomas and in six out of 14 leiomyomas. In non-neoplastic muscle cells, occasional weak bcl-2 positivity was found in muscle cells of vascular walls and myometrium. In mesenchymal tumours of other lineages, bcl-2 positivity was only found in four out of 12 malignant fibrous histiocytomas and in one out of three liposarcomas. p53 positivity was found in 14 tumours, 13 of which were sarcomas. No association was found between p53 and bcl-2 positivity. Our results suggest that bcl-2 expression is activated significantly more often in muscle derived tumours than in mesenchymal tumours of other lineages. Our results also suggest that p53 status does not directly affect the expression of bcl-2 in sarcomas.