CDKN2A and Pleural effusion: Nevertheless, presence of cellular atypical features, demonstration of mesothelial differentiation and of some genetic alterations including cyclin-dependent kinase-inhibitor 2A/p16 and neurofibromatosis type 2 (NF2) or lack of BRCA1-associated protein 1 (BAP1), alone or in combination, may effectively distinguish MPM from metastasis in samples, from pleural effusions (Figure 15).