E2F1 and head and neck squamous cell carcinoma: The overexpression was described of genes involved in DNA replication and proliferation such as E2F transcription factor 1 (E2F1), centromere protein F (CENPF), maternal embryonic leucine zipper kinase (MELK) and replication factor C (activator 1) 4 (RFC4) in various independent microarray studies performed on HPV-infected CC and head and neck squamous cell carcinomas (HNSCC).