Hi. In this video, I'm going to be talking about metastasis. So what is metastasis? It is the ability of cancer cells to enter into the bloodstream and travel throughout the body and invade those tissues in very distant bodily organs and cause cancer there. The interesting part of this is when we think of cancer, we often think that, oh, it's so easy. Cancer is just going to quickly metastasize to other parts of the body. But this actually isn't the case. Very few cells can survive traveling through the bloodstream. But the cells that do typically enter the bloodstream, travel to the lymph nodes where they set up shop, which is often what we hear, people having, you know, benign cancer, but it's also in their lymph nodes. So that's kind of the first step. Setting up shop then, but eventually, they will travel more and to more distant tissues away from the primary tumor, which is the first tumor that formed.
We actually don't have a really good idea about what causes cancer cells to metastasize. We know that they do, and they do it often, but, I mean, I can't present to you, you know, this happens first, this happens second. The only thing I can tell you is that there's a GTPase, Rho GTPase, that is important for metastasis. So we know that if cancer cells don't have this, or if it's acting properly, then, generally, they don't metastasize, but no one is really sure of the pathway. How does Rho GTPase prevent against metastasis? No one really knows. But they're thinking that this is kind of the place to start.
Now the other important thing to talk about metastasis is talking about the tumor microenvironment. So this is going to be the environment in which the tumor lives. You can imagine that the environment can have a big effect on the tumor, so it can influence the tumor's growth. It can influence whether it can invade and metastasize. So this includes all the nutrients or the growth factors or things surrounding the cell and the tumor. The tumor microenvironment can also support this process called angiogenesis, which we talked about before. And angiogenesis is the growth of new blood vessels where they really shouldn't be. So we don't normally, you know, grow new blood vessels in the middle of, you know, our organs, whether, wouldn't necessarily need to be anything. But tumor cells produce this large mass that needs nutrients, and so angiogenesis is the process of forming those, blood vessels in these big tumor masses. This is because tumors that lack a blood supply will die because they don't have oxygen and they don't have nutrients. So a lot of cancer treatments are actually now trying to target the formation of blood vessels, right, because if we know that tumor cells can't form these blood vessels, then, they will eventually die because they don't have a new chance.
So here's just a very simple diagram. You can see, cancer cells. So here is an original tumor. You can see it's invading into the bloodstream. It's traveling. We can imagine it travels pretty far away, but eventually, it will exit and form this secondary tumor, and it's some type of distant location, whether, in a local lymph lymph node nearby or completely across the body in a completely different organ. So that's metastasis. So with that, let's now turn the page.
