Immunoreactivity for bcl-2 protein in malignant mesothelioma and non-neoplastic mesothelium.

Immunohistochemical study of bcl-2 protein immunoreactivity in human non-neoplastic mesothelium (44 cases) and in malignant mesothelioma (62 cases) using a murine monoclonal antibody (clone 124) showed cytoplasmic immunoreactivity for bcl-2 protein in five cases of malignant mesothelioma. Non-neoplastic mesothelium was not immunoreactive. Immunoreactivity for bcl-2 protein does not add useful prognostic information in malignant mesothelioma since survival times of bcl-2 positive and bcl-2 negative cases did not differ. Nevertheless, the detection of bcl-2 protein in malignant mesothelioma might be useful for the differentiation from reactive mesothelium.