The recognition of a causal relationship between human papillomaviruses and 
cancer almost 30 years ago led to a rapid expansion of knowledge in the field, 
resulting in the description of the main mediators of HPV-induced 
carcinogenesis, the viral proteins E6 and E7. These oncoproteins show a 
remarkable pleiotropism in binding host-cell proteins, with the tumour 
suppressor genes p53 and pRb as their major targets. These interactions induce 
proliferation, immortalization and malignant transformation of infected cells. 
The link between HPV and cervical cancer led to the development of molecular 
methods, often based on the detection of E6 and E7, for screening and diagnosis. 
Therapeutic vaccines and gene therapy are primarily directed at E6 and E7. 
Although prophylactic vaccines are available, further understanding of the viral 
life cycle and the mechanisms underlying HPV-induced oncogenesis is necessary to 
face the many challenges in the field of HPV and cancer.