BAP1 and peritoneal mesothelioma: Although the two cases in this article are insufficient to establish a definitive treatment paradigm, they strongly suggest the future development of a stratified treatment approach based on anatomical location: peritoneal mesothelioma should be treated with immunotherapy combined with chemotherapy (based on our experience and growing literature), while pleural mesothelioma should integrate molecular subtype analysis from the outset of treatment (e.g., targeted therapy for BAP1-deficient patients) (4).