Lee HE, et al. - The prevalence of BRCA1-associated protein 1 (BAP1) loss in well-differentiated papillary mesothelioma (WDPM) by immunohistochemistry with clinical correlation, along with CDKN2A deletion status by fluorescence in situ hybridization (FISH) was investigated in this study. Researchers identified eight patients diagnosed as WDPM from the surgical pathology file. They reported that WDPM did not show CDKN2A deletion in any case. They observed that BAP1 loss was also absent in all pure WDPM cases though was identified in all WDPM with synchronous or metachronous MM. Data showed that similar genetic landscape in WDPM and MM components suggested their clonal relationship.