Carcinogens

Hi in this video I'm gonna be talking about carcinogens. So we have talked about the fact that cancer begins with mutations in the DNA of a cell. So the cell gets those mutations through things called carcinogens. And carcinogens are substances molecules that induce DNA damage which can lead to cancer in some cases. So there's two types of carcinogens. The first is an initiator and these are carcinogens that directly damage the D. N. A. So they interact with the D. N. A. And damage it directly. Then we have two more promoters and these are carcinogens that don't cause mutations but sort of promote cancer. That's all promote cancer that already has some type of mutated DNA. To remember cancer isn't just one mutation it's an accumulation of mutations and it's a accumulation of other factors to proteins and extra cellular factors that can lead to cancer. So initiators are the ones that actually damage the DNA cause those mutations. But promoters don't cause mutations that cause sort of promote the cell to turn into cancer if it already has mutations. So here's an example of a tumor initiator. So we have a carcinogen, it interacts with the D. N. A. Causes damage. There's some type of DNA repair deficiency. So for instance the tumor promoter, it could happen here where it takes away some factor say for instance calcium that would that would help signal for DNA repair. Um some type of deficiency here and the combination of DNA damage the lack of repair, causes more DNA damage and all of this will eventually lead to cancer again not just one factor, but multiple of them. So when I talk about DNA damage, I'm talking about things like the loss of the DNA repair system. Telomere shortening. Remember the telomeres at the end of chromosomes are replicated differently. Um and that it can induce the shortening over time. Well, if they, you know, that's obviously if you're losing a part of the telomere, that's obviously some type of DNA damage, but it also can include things like viral genome integration. So we know that some viruses when they infect the cell, they ingrate their integrate their genome into the cell and that could be a type of DNA damage as well. So examples of carcinogens that you're probably familiar with, these are things like tobacco, which is a huge carcinogen and this actually can directly damage the DNA itself. You have viral exposure. The viruses that can lead to cancer. These human papilloma virus, hepatitis B, hepatitis C. These viruses can lead to cancer. And then there are some diet and lifestyle choices. Of course these are a little bit more controversial but generally, you know, eating healthy and having, you know, some type of exercise can help do a lot to um you know, help prevent cancer in the population as a whole. So that's kind of a general overview of carcinogens, how they work. And some examples of some. So with that, let's now turn the page

All carcinogens act by directly damaging DNA.

• A. True
• B. False

Which of the following is not a type of DNA damage?

• A. Loss of DNA repair and accumulation of mutations
• B. Shortening of telomeres
• C. Epigenetic modifications leading to gene suppression
• D. Integration of a viral genome