MDM2 and mesothelioma: By contrast, expression and phosphorylation of MDM2, in three normal MDM2 mesothelioma cell lines (JMN1B, MESO924, and MESO296), and expression of p53, in two p53 wild-type mesothelioma cell lines (MESO924 and MESO296), were unchanged or slightly affected after treatment with HDACi (Figures 2 and 3A).