HPV-16 E6 and E7 oncogene expression is downregulated as a result of Mdm2 knockdown.

The carcinogenic potential of HPV infections is based on the integration and constitutive expression of the E6 and E7 genes which inhibit the p53 and Rb tumor suppressor proteins. In normal cells, Mdm2 regulates p53 in a negative feedback loop, and although Mdm2 is apparently functional in HPV-infected cells, E6 is the protein responsible for repressing p53 replacing Mdm2 function. The role of Mdm2 in HPV-positive cells is still elusive.