Common acquired melanocytic nevi are benign neoplasms that are composed of small uniform melanocytes and typically present as flat or slightly elevated, pigmented lesions on the skin.,We describe two families with a new autosomal dominant syndrome characterized by multiple skin-colored, elevated melanocytic tumors.,In contrast to common acquired nevi, the melanocytic neoplasms in affected family members ranged histopathologically from epithelioid nevi to atypical melanocytic proliferations that showed overlapping features with melanoma.,Some affected patients developed uveal or cutaneous melanomas.,Segregating with this phenotype, we found inactivating germline mutations of the BAP1 gene.,The majority of melanocytic neoplasms lost the remaining wild-type allele of BAP1 by various somatic alterations.,In addition, we found BAP1 mutations in a subset of sporadic melanocytic neoplasms showing histologic similarities to the familial tumors.,These findings suggest that loss of BAP1 is associated with a clinically and morphologically distinct type of melanocytic neoplasm.
Because only a small fraction of asbestos-exposed individuals develop malignant mesothelioma1, and because mesothelioma clustering is observed in some families1, we searched for genetic predisposing factors.,We discovered germline mutations in BAP1 (BRCA1-associated protein 1) in two families with a high incidence of mesothelioma.,Somatic alterations affecting BAP1 were observed in familial mesotheliomas, indicating biallelic inactivation.,Besides mesothelioma, some BAP1 mutation carriers developed uveal melanoma.,Germline BAP1 mutations were also found in two of 26 sporadic mesotheliomas: both patients with mutant BAP1 were previously diagnosed with uveal melanoma.,Truncating mutations and aberrant BAP1 expression were common in sporadic mesotheliomas without germline mutations.,These results reveal a BAP1-related cancer syndrome characterized by mesothelioma and uveal melanoma.,We hypothesize that other cancers may also be involved, and that mesothelioma predominates upon asbestos exposure.,These findings will help identify individuals at high risk of mesothelioma who could be targeted for early intervention.