BAP1 and pleural mesothelioma: Although the link between asbestos exposure is not as strong for peritoneal mesothelioma as for pleural mesothelioma, up to 60% of patients have been exposed to asbestos.3,29 Other environmental agents such as zeolite fibers, a mineral found in volcanic tuff, also have been associated with mesothelioma development.30 In addition to environmental agents, other risk factors are germline BAP1 mutations and other deleterious mutations of tumor suppressor genes.31,32 All risk factors considered, asbestos exposure seems to be the largest contributor to MPM risk.