Question: how do people get cancer?

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  1. It is often difficult to find out how or why people got cancer. This is firstly because there are many possible causes and secondly because what caused the cancer may have happen many years before the cancer was found.

    Sometimes the cause is easily found. For example, mesothelioma is almost always caused by exposure to asbestos, but this may have happened many years or decades before. Skin cancer is thought to be triggered by too much UV exposure. But the cause of other cancers is often impossible to figure out.

    What ever caused the cancer, cancers usually start when the DNA of a cell gets damaged. This damage might not be able to be repaired by the body. Usually the body can just kill off that one cell, but if the DNA is damaged in certain places, the body can no longer kill off the damaged cell. Instead, the damaged mutant cell keeps growing and multiplying to form a tumour.


  2. Yes, Bridget’s point about the cause maybe happening a long time ago is a really good one.

    Also, people know they have cancer when it becomes a problem, or they become sick, or it’s seen in some random test. I’ve always wondered how much the body deals with cancer everyday, and we don’t see it. On a molecular level each cell is constantly checking and re-checking your DNA for mistakes, and if the cell finds a mistake it rubs it out and starts again, either by repairing the DNA or by killing the cell. The cell is really busy doing this. Even so, some damage is not corrected and the cell starts making copies of itself too quickly, and that’s when trouble starts.

    There are so many causes. Sun, maybe even bad diet – a good, healthy diet contains a lot of things that can prevent cancer on a very simple level. What you hear about antioxidants being good for you is basically true – fruit and veg help. Staying out of extreme sun. Not smoking. But there are other things that you can’t do much about, and that’s where medicine kicks in.

    You know there are even some viruses that will cause cancer. They’re called “oncoviruses”. These are pretty rare in everyday life, and certainly not all viruses cause cancer! They’re often used in labs to create cancer so we can study is in a model system. I remember an amazing thing at school – when I was 17. I don’t remember how, but our bio teacher managed to get hold of a cancer-causing virus and injected it into the stem of a plant. A week later we came back and there was this big growth on the side of the plant. That freaked – me – out.

    So “cancer” is a complicated thing. It’s why there won’t ever be a “cure” for cancer, because there are lots of different types. If you study biology and biochemistry you’ll learn all about this stuff, which is both interesting an important.


  3. There is no single cause of cancer. Normal cells grow and live. Most cells divide to form two cells from a single cell. Cancer is usually when some cells have uncontrolled growth, which then interferes with normal cells. As Bridget and Matt have written lots of different things might cause this.


  4. It’s so difficult to know. So many things can lead to cancer and many have been mentioned by everyone else here. And there is more than one type of cancer so finding a cure doesn’t mean finding one, there needs to be a different approach to each cancer. And then added to that, cancer behaves differently in everyone who “gets” cancer. A treatment may work in one person but in another it may not.

    This is why there is so much cancer research. There is so much that is unknown.

    There is also this comic on cancer and cancer research.


  5. Cancer is the name for a large collection of diseases in which cells grow abnormally. Because it’s not on single disease, or one type of problem, you can’t use the same treatment for every type.

    Cancer arises from a single cell (it can be any type of cell in your body) which has been damaged in a way that makes it live when it is supposed to die and produce many copies of itself. The more copies the cancer cell makes, the more mistakes there are in the DNA of the new cells because the normal proof-reading systems shut down. This allows the cells to become even more nasty and more likely to escape from where they started and invade another part of your body.

    Cancer is the result of damage to the DNA of your cells. This can be caused by so many things that it is hard to tell which ones are responsible. This damage can happen over a long time, not becoming a problem, or even noticeable, for many years. Some things which are known to cause cancer are UV in sunlight, the chemicals in cigarettes and some inherited diseases. The causes of a lot of types of cancer are still unknown.