Human papillomavirus immortalization and transformation functions.

The high risk HPVs (such as HPV-16 and HPV-18) that are associated with specific anogenital cancers encode two oncoproteins E6 and E7, which are expressed in the HPV positive cancers. The E7 protein functions in cellular transformation, at least in part, through interactions with pRB and the other pRB related 'pocket proteins'. The major target of the E6 oncoprotein encoded by the genital tract, cancer associated human papillomaviruses is p53. Several lines of evidence suggest that E6 and E7 have additional targets important to the oncogenic potential of the virus. Work from a number of laboratories has focused on determining other activities of HPV relevant to carcinogenesis and identifying additional cellular targets of E6 and E7. This paper will review the state of the field at the time of the 19th International Papillomavirus Workshop in September 2001 with respect to the HPV encoded oncoproteins.