CDKN2A and lung cancer: As observed with the lung cancer cell line, the cell cycle regulator Cdc2, Fanca and Cdc25c were downregulated, while the kinase inhibitors Cdkn1a and Cdkn2a as well as cyclin-dependent kinase 5 (Cdk5) were upregulated as was expression of the p53-inhibitor Mdm2.