This cancer arises from the mesothelial cells that line the pleural, pericardial, and peritoneal surfaces. Although classically associated with asbestos exposure, familial clusters of mesothelioma may occur suggesting that genetic factors may influence susceptibility (Carbone et al. 2007). Testa et al. (2011) demonstrated that germline mutations in BAP1 predisposed to mesothelioma, uveal melanoma, and possibly other cancer types, and it has been suggested that the occurrence of mesothelioma and melanoma in BAP1 mutation carriers may depend on exposure to asbestosis and sunlight. The relative frequency of peritoneal to pleural mesothelioma appears to increase in inherited cases compared to sporadic cases.