CDKN2A and cancer: Here, we first aimed to assess the efficacy of first-generation CDK4/6i, ribociclib, palbociclib, and abemaciclib, on our panel of DPM cell lines characterized by the loss of CDKN2A. As expected, all CDK4/6i showed efficacy in reducing DPM cell viability, whereas normal immortalized MET-5A mesothelial cells were not affected by palbociclib at the range of concentrations tested or affected by abemaciclib and ribociclib at higher doses compared to those inhibiting cancer cells.