Therefore, to determine the role of Brd4 in HPV18 gene expression at very early stages of infection, subconfluent HFKs were depleted of Brd4 with two different small interfering RNAs (siRNAs) and infected 24 to 48 h later with 100 VGE/cell of HPV18 quasivirus. This evidence concerns the gene BRD4 and infection.