How Can HPV Infection Lead to Cancer?

As we learned, after cellular infection the HPV genes are expressed within the host cell. A number of these viral genes have the ability to interact with the host's cellular pathways that control mitotic cell division.

Protein	Mechanism of Action
E1	Acts as a DNA Helicase
E2	Recruits E1 to the viral origin of replication
E5	Hydrophobic transmembrane protein that modulates the activity of Epidermal Growth Factor and its tyrosine kinase activity. E5 causes the cell to be unable to respond to paracrine growth inhibitory signals.
E6	Binds to p53 and initiates the degradation of p53 and Induces telomerase
E7	Binds to Rb; facilitates the release of E2F
L1	Major Capsid Protein
L2	Minor Capsid Protein

Review the function the protein of each of these viral genes produces and predict its effects on the cell.

Predict the role of E1 and E2 on the viral life cycle. Justify your prediction.
Predict the effect of E6 on the regulation of the cell cycle. Justify your prediction.
Predict the effect of E7 on the regulation of the cell cycle. Justify your prediction.
Predict the effect of E6 and E7 on a cell that has experienced significant DNA damage. Justify your prediction.
Predict the effect on the cell cycle that was affected by E5. Justify your prediction.

By the time L1 and L2 are expressed multiple copies of the viral genome have been produced.

What will assemble within the host cells once L1 and L2 are expressed? Justify your answer.

The diagrams below illustrates some of the important steps necessary for HPV infection to lead to cancerous tissue.

Using the diagrams -

What events are necessary to transition normal cervical cells to cervical neoplasia?
What events are necessary to transition to invasive cancerous cells?
How long does it take for cervical cancer to develop?
Do all individuals infected with HPV develop cervical cancer?

Cervical Cancer