Your Body Killed Cancer 5 Minutes Ago

Somewhere in

your

body

,

your

immune system simply silently

killed

one of your own cells, preventing it from turning into

cancer

and saving your life. She does it all the time.   The vast majority of

cancer

cells you develop will die without you realizing it. Which is incredibly difficult work because of what cancer cells are: parts of yourself that start behaving like individuals even if it hurts.   What is cancer and how does your

body

kill it all the time? INTRO Cancer occurs when corrupt cells multiply uncontrollably. It can arise from basically any type of cell in the body, so there is not just one type of cancer, but hundreds.   Some grow slowly, some are aggressive, some can be treated effectively, and some are fatal.

In a sense, a cell that becomes cancer becomes something old and something new. Over billions of years, evolution has shaped cells to survive and thrive in a hostile environment, fighting for space and resources. Until a new and exciting way of life emerged: cooperation, a division of labor that allowed cells to specialize and be more successful together.   But cooperation requires sacrifices. For a multicellular being to remain healthy, the well-being of the collective has to matter more than the survival of the individual cell. Cancer cells stop being part of the collective and become individuals again.   Your body can handle some wayward cells, but some cancer cells divide again and again, becoming a kind of new organism inside you.

Taking the resources you need to survive, competing for the space you inhabit, destroying in the process the organs they were a part of. Despite the damage they cause, cancer cells are not bad. They don't want to hurt you.   They don't want anything. Cells are protein robots that simply follow their programming, which has unfortunately been corrupted. The soul of the cell Simply put, cells have a nucleus full of DNA. It consists of genes: instructions on how to build proteins and when to produce each one. These building instructions are copied and transferred to ribosomes, where they are used to make proteins.

The type of proteins your cells produce determines what they can do. The important thing here is that a corrupted gene means you get a corrupted protein, which will become important later. Your DNA becomes slightly corrupted (mutated) tens of thousands of times a day.   Most of the time without any special cause, simply by being alive.   Almost all of these mutations resolve very quickly or are not problematic. Still, over time, as cells make copies of themselves, the damage accumulates. Imagine having to make copies of copies of copies for decades. Maybe one day a hair fell out of the scanner or a corner frayed.   Each new error becomes part of the new copies and all subsequent copies.

You can increase DNA damage by smoking, drinking alcohol, being obese, breathing asbestos, not using sunscreen, or contracting a virus like HPV. But the easiest way to damage DNA and get cancer is to live long enough.   For many cases of cancer, there is no other cause than bad luck. Damage Leading to Cancer We're simplifying, but broadly speaking, there are three categories of genes that must be corrupted for cancer to arise. The first key mutation is found in the appropriately named tumor suppressor genes, or TSGs.   These genes are a lot of things. On the one hand, they produce control mechanisms that continually scan your DNA for errors and copying errors and correct them immediately.

And then they prevent normal cells from multiplying recklessly. If the TSGs become damaged, your cells basically forget how to repair themselves and can reproduce uncontrollably. The second crucial mutation may occur in their oncogenes. When oncogenes are activated, the cell is told to multiply rapidly. They were super active when you were inside your mother's womb.   To turn a single original cell into trillions in months, it needs to divide and grow rapidly. These fast-growing genes are turned off when there is enough of you.   When your oncogenes become corrupted, they basically turn on again. The third crucial mutation is in your cells' suicide switch.   Most cells are constantly recycled and refreshed.  When cells accumulate too much damage, they usually notice it and special genes trigger a controlled suicide called apoptosis.

If the genes that control this process are damaged, the cells are free to continue living despite being dangerously corrupted. So if a cell becomes unable to correct errors in its genetic code, loses the ability to destroy itself when it notices damage, and begins to grow rapidly without restrictions, it becomes a young cancer cell. These cells need to be

killed

as quickly as possible: while they are bad at this stage, they are still quite weak and easy to kill. But if they continue to mutate and increase in number, they can learn to bypass your defenses and become a real threat.  At any time in your life, your immune system is hunting these cells.

But how do you identify and kill corrupt cells that appear indistinguishable from healthy ones? How to Find Cancer Well, here we return to the proteins that cells make and the story they tell. So if, for example, their oncogenes become activated again, they produce oncogenic proteins. Your immune system knows they shouldn't be present if you're an adult. So, to know which cells are corrupt and which are healthy, your immune system needs to know what proteins they are producing inside. To solve this evolution, MHC class I molecules were devised, a kind of viewing window that makes cells transparent.

Cells are constantly taking small samples of the proteins they make and putting them on thousands of these MHC molecules to show what they are doing.   The selection is constantly updated and always offers an up-to-date image. There is a whole library of proteins that are very dangerous and should not be made by healthy cells, and your immune system has them all on file. It has billions of specialized cells, called T cells, created to recognize specific proteins. If a T cell sees a banned protein in an MHC display window, it knows the cell is corrupted and kills it immediately.

But there is a flaw in this system. What happens if a cancer cell mutates and finds a way to bypass this process? All you need to do is stop producing MHC Class I molecules and, boom, you're invisible.   Without window dressings, the immune system is blind and can no longer identify cancer. Fortunately, evolution found an ingenious solution:   The natural killer cell. A judge, jury and executioner. The Killer At this very moment, hundreds of millions of natural killer cells patrol your body in search of cells that have already turned into cancer or are corrupted by a virus. Natural killer cells go from cell to cell to check one thing: Does a cell have MHC class I molecules?

Do you have a shop window and are you doing your duty to show what goes on inside? This is so surprising because it covers all your bases: while T cells look for the presence of the unexpected, something that shouldn't be here, natural killer cells look for the absence of the expected, the absence of something that should be here. The logic is: if a cell has no viewports, it wants to hide something. And a cell that hides something must be eliminated. What makes Natural Killer Cell even more metal is that it is always in killer mode. It patrols your body, checking cell after cell with the intention of killing it.   Your healthy cells have to convince you that they shouldn't die today.

And one way to do this is to have MHC class I molecules. In short, almost all of the young cancer cells you will develop in your life will be eliminated by your immune system. Okay, but if your body is this prepared, why do we still have cancer? Well, sometimes cancer cells mutate more and fight back much better.   Cancer is the story of an arms race. An arms race that we will eventually win, perhaps with the help of natural killer cells! Right now, a number of therapies are starting to show surprisingly promise, from cancer-fighting vaccines to engineered T cells and even natural killer cells.

We will look at these therapies in future videos.  So the war is not won yet, but we are on the path to cancer and it will eventually be eliminated once and for all, perhaps sooner than we think.