Previous immunohistochemical analyses for BAP1 protein have demonstrated that patient-associated deletions, insertions or point mutations all lead to loss of nuclear staining, even though cytoplasmic staining is present in some patients [8, 39], Here, we evaluated the expression of BAP1 and BRCA1 protein in tumour samples taken from chemonaive mesothelioma patients undergoing extended pleurectomy decortication (n = 26) using immunohistochemistry (Fig. 1C). This evidence concerns the gene BAP1 and mesothelioma.