Malignant mesothelioma is an aggressive tumor of the mesothelium that arises most commonly in the lungs and chest wall subsequent to asbestos exposure. Some individuals with BAP1 mutations may have a predisposition to mesotheliomas. Antibodies such as HMBE-1 (Human bone marrow endothelial cell marker-1, marker of mesothelial cells) can help identify malignant mesothelioma in immunohistochemistry and may be used to distinguish it from adenocarcinoma. References: BMC Res Notes. 2016 Jun 24;9:324, PMID: 27342200; Korean J Pathol. 2014 Apr;48(2):91-9, PMID: 24868221; Pathology. 2009 Feb;41(2):140-8, PMID: 19152187; Testa et al. 43(10):1022-5 - Nature Genetics;