The fact that most BAP1-TPDS-related neoplasms arise in middle-aged and older adults, and that the penetrance for any cancer type associated with this syndrome is less than 100% (e.g., 25–35% for mesothelioma [2,22,30] suggests that genomic alterations in addition to BAP1 loss are required for cancer formation [31]. This evidence concerns the gene BAP1 and cancer.