CDKN2A and cancer: To investigate the role of the IFN-Stat1-dependent activation of Cdkn2a, what encodes alternatively spliced variants, including the structurally related CDK4 kinase inhibitor isoforms p16Ink4a and p19Arf, we analysed the immune control of transplanted cancer cells isolated from RIP-Tag2 mice, where expression of the T antigen under the control of the rat insulin promoter (RIP) leads to pancreatic islet cancers (RT2-cancers)25.