This family includes the E7 oncoprotein from various papillomaviruses []. Along with E5 and E6 their activities seem to be especially important for viral oncogenesis. E5 is located at the cell surface and reduces cell gap-gap junction communication. In cervical cancer E5 is expressed in earlier stages of neoplastic transformation of the cervical epithelium during viral infection. The role of E7 is less well understood but it has been shown to impede growth arrest signals in both NIH 3T3 cells and HFKs and that this correlates with elevated cdc25A gene expression. This deregulation of cdc25A islinked to disruption of cell cycle arrest [].
