Viruses are infectious agents that can replicate only within the cells of other
living organisms. Humans are affected by a variety of viruses. Some cause minor
illnesses like the common cold; others can lead to more serious conditions
like influenza and AIDs.
Click on the buttons to the left to find out more about the human papillomavirus
(HPV) and its link to cervical cancer.
HPV
Human papillomavirus (HPV) is a large family of viruses best known for causing
warts. Some HPV types have been linked to cervical cancer.
Click the forward arrow or the numbers below to find out more about the human
papillomavirus (HPV).
Bettie Steinberg, Ph.D., talks about HPV and its prevalence among the population.
O.K. HPVs are a family of related viruses. They're in a group called the small
DNA tumor viruses, which means they have DNA inside the virus and can cause tumors
in either their natural host or another organism. The HPV are human papilloma
viruses. There are more than a hundred different types and they are extremely
common. Some of the types cause skin warts, or plantar warts. Other types infect
the mucus membranes and they cause things like genital warts and genital tract
infections. They are extremely common. Everybody has these viruses. We have them
in our skin and they live within our mucus membranes. They live with us. And
the estimate is that at least 70% of women will have a HPV infection of the genital
tract, primarily the cervix at some time, during their life.
Denise Galloway, Ph.D., talks about HPV and its link to cervical cancer and how
HPV infection affects normal cellular processes.
There are many HPVs that infect the genital tract and a set of those cause benign
genital warts but another set is able to cause lesions that will go on and progress
to cervical or other genital cancers. I think the link is very firmly established.
There are, have been many large international studies that have looked for the
presence of HPV in cervical cancer and found that nearly 100% of them are positive
for the viral DNA. I think the mechanisms are pretty well understood. HPV infects
the genital epithelium. It causes those cells to proliferate when they normally
would not. It also causes the normal checkpoints that would prevent the cell
from replicating if there is DNA damage or damage to the chromosomes, it inactivates
those checkpoints so that the cells that receive damage can still continue to
replicate.
Viruses don't want to cause cancer, they just want to make more virus. But this
virus has really none of its own machinery for replication. And so the only way
it can replicate itself is to be in a cell that’s replicating, so that
it can use the cellular replication machinery. So it gets into a cell and in
order to make its viral proteins, it needs to push that cell into cellular replication.
And it does so with the expense of the cell's normal control. Normally the outcome
is that you get more virus. So cancer is a very rare outcome for HPV infection.
HPV and cell cycle
Cell growth and replication are tightly regulated processes. Viral proteins disrupt
this growth cycle by interacting and binding with host proteins.
Click the forward arrow or the numbers below to find out more about the cell
cycle and how human papillomavirus (HPV) viral proteins interact with cellular
proteins.
Vaccine
Vaccines work by stimulating the body’s immune response to a virus. The
body then produces antibodies that will attack and remove the virus thus preventing
infection.
Click the forward arrow or the numbers below to find out more about vaccines
directed against human papillomavirus (HPV).