Epidemiological studies show that infection with a subset of genital human papillomavirus (HPV) infections is the major risk factor for the subsequent development of cervical cancer. Experimental studies show that that the E6 and E7 genes of these high risk HPVs are oncogenes that deregulate key cell cycle controls. In the normal infectious cycle high level expression of these genes is confined to non-dividing differentiated cells: HPV oncogenesis requires deregulation of viral and cellular genes permitting inappropriate expression of E6 and E7. These are rare events but viral persistence and chronic exposure to steroid hormones increase the probability of this deregulation.
Copyright 2001 Harcourt Publishers Ltd.