Additional studies demonstrated that DEK was an E2F transcription factor target gene, explaining its upregulation in response to retinoblastoma protein inhibition by E7 [66]. Dek knockout (Dek−/−) mice are resistant to HPV E6 and HPV E7 driven squamous cell carcinomas, supporting a critical role for DEK function in HPV-induced tumors [64]. This evidence concerns the gene DEK and squamous cell carcinoma.