CDKN2A and pleural mesothelioma: In pleural mesothelioma, Group 1 had alterations in CDKN2A/B and BAP1, Group 2 in CDKN2A/B only, Group 3 in BAP1 only and Group 4 in neither BAP1 nor CDKN2A/B (Fig. 3 and Tables 1 and 2).