Tumor Viruses

Hi in this video I'm going to be talking about tumor viruses. So there are many types of tumor viruses and these we also call Anka genic viruses. And these are viruses that cause cancer or can cause cancer. They don't always but they can and so somehow these can do it by a couple of different ways. One way is by actually having that genome integrate into the host cell. So the viral genome comes in and infects and integrate somewhere into the host cell genome. And obviously that can be harmful. Say you into. So you to say the virus puts an entire genome in something like grass which we've talked about the G. T. P. A. S. Well if it's in wrasse that's obviously going to mess up grasses function. And we know grasses mutated in a lot of different cancers. So this could be extremely harmful and very easily lead to cancer. But other viruses don't necessarily have to integrate themselves in order to cause or lead to cancer. They can just have proteins which interfere with normal cell functions and that leads to cancer. So for instance if you have a protein that blocks a tumor suppressor activity, you're going to lose the function of the tumor suppressor. It's going to be the loss of activity and that can lead to cancer, you can have proteins that interfere with cell cycle control. Say for instance increased cell cycle control which would be beneficial for viral replication or decrease apoptosis which again would be very beneficial for the virus. Um So you can imagine how the virus has these proteins that would decrease apoptosis and increase the cell cycle. So the virus can replicate without dying. So these very easily could happen. And then other viruses have proteins that can take over the cell replicated machineries or cell replication or DNA replication in order to replicate genome. So the virus infects the cells so that it can replicate itself. So it has to take advantage of the sales mechanisms in order to replicate itself. So obviously these proteins are going to take over all of that machinery and say no, I'm going to use it for myself and I'm going to overuse it and over express it so that I can generate a lot of myself. So that virus will generate a lot of itself. So here's some examples of some viruses. This is not an exhaustive list by any means, but these are kind of something that you probably should be familiar with. These are things like hepatitis B and C, which are associated with liver cancer. You have the papilloma virus is probably the one you're most familiar with is human papilloma virus. There's a vaccine against it. This thing called cervical cancer as well as head, neck and throat cancer and the second one in men and women. So it's not just a female cancer, You have herpes virus, This can cause an interesting cancer called Kaposi's sarcoma and this is most often associated with retroviruses, um not because the retrovirus actually causes Kaposi's sarcoma, but instead the retrovirus leads to AIDS, which is a syndrome that really decreases your immune system's ability to fight off infections. So then you very you know you can get these herpes virus infections that lead to this cancer. Um So we often times say HIV is associated with Kaposi's sarcoma but it's because that lowers your immune system causes these other viral infections. So um I said there were some proteins that could interfere with cell functions. I want to introduce a couple. So these are human papilloma virus. You have a protein called E six and approaching called E seven. So when the human papilloma virus infects a cell, these proteins are expressed and then they go on to interfere with the cells functions over in Says the six protein combined the transcription factor three. Now if it's binding this transcription factor which is also a tumor suppressor, it actually leads to its destruction. So now you're destroying a tumor suppressor, you're losing that activity obviously can promote cancer. Then you have the seven protein. This combined to the retinoblastoma tumor suppressor which we've talked about and when it's bind to it it actually doesn't destroy it but it does inhibit its function. So again you're inhibiting this tumor suppressor, you're losing that activity and that is resulting in this high probability that a cancer cell or tumor cell will form. So that's an overview of tumor viruses or uncle genic viruses. So with that let's now move on

Many viruses can cause cancer.

• A. True
• B. False

Which of the following viruses can cause head, neck, and throat cancer?

• A. Hepatitis B
• B. Human Papillomavirus
• C. Herpesvirus
• D. Retroviruses