It has recently been demonstrated that BAP1 alterations represent a very early event in the development of a subset of mesotheliomas; however, to date, the evidence supports that BAP1 and CDKN2A loss occur in up to 70% of cases, and therefore the diagnosis of MPM cannot certainly be excluded in the absence of these molecular abnormalities [28]. This evidence concerns the gene BAP1 and mesothelioma.