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Asked by littlepwincess to Sarah, Tim, Dalya, Derek, Tom on 19 Jun 2011. This question was also asked by rubii, alliyia, xxfaduma123xx.
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Tim Millar answered on 14 Jun 2011:
Cancer can start for a range of reasons including infection from viruses, environmental exposure like UV from the sun or because something goes wrong with the information in our cells which is needed to make new cells.
Normally, cells divide to make more cells but when they are told to stop, they stop. For some reason, cancer cells don’t understand this stop signal and carry on dividing and making more of themselves. They then don’t always do the job that they were made for, so for example, liver cells which turn into cancer, stop doing their liver job. We need our liver to survive normally, so if the cancer takes over we cannot reproduce what the liver does so we biocome very ill indeed.
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Sarah Thomas answered on 14 Jun 2011:
The fundamental cause of cancer is damaged or faulty genes – the instructions that tell our cells what to do. Genes are encoded within DNA, so anything that damages DNA can increase the risk of cancer. When a new cells grows with this faulty DNA, it just doesn’t look right and then it grows and spreads really fast, and quickly forms a big lump of faulty cells called a tumour.
Things that damage your cells and DNA are things like smoking, drinking alcohol, eating unhealthy foods, and sun tanning.
As you get older your risk of getting cancer increase. This is because the older you are, the more times your DNA has been copied and your cells copied and errors can start to creep in.
It all comes down to risk really. Everybody has a chance of getting cancer, and for some people, their lifestyle means their risk is higher. The really sad thing is that a perfectly healthy person who never smokes or drinks can get cancer too.
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Dalya Soond answered on 14 Jun 2011:
Every time a cell divides, it will make little mistakes while copying its DNA. And is that any wonder either? It needs to copy about 250 million pieces of DNA every division. That’s quite a task.
The copied DNA is proofread by different enzymes and if mistakes (mutation) are found, the mistake will be fixed or the cell will be killed. Unfortunately, mistakes aren’t always caught.
Most of these will not affect the cells much, but sometimes it will allow the cell to divide more easily or resist death or not be able to proofread copied DNA well. If you get a few of these mutations in complementary genes, you can start the process of getting cancer.
So then the cell can divide very quickly and fail to fix mutations that may change other behaviour in the cell such as metastasis (the ability to digest through tissue, travel to other organs, and set up colonies of cancer cells there).
As an extra note, it is not just the damaged cell itself who has to either try to fix a mutation or kill itself. If the immune system sees a cell that looks like it is becoming cancerous, it can try to kill it too. This is my main topic that I study nowadays.
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Derek McKay-Bukowski answered on 14 Jun 2011:
Good question. There is no way I can compete with the other sci’s on this one.
However, I would add that there are lots of ways of of starting this damage. In addition to the ones people usually thing of (such as smoking and UV from the sun), many chemicals are ‘carcinogenic’ (a term which means that they cause cancer). Also problematic are forms of radiation (from, for example, certain radio isotopes).
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Tom Crick answered on 19 Jun 2011:
Some good answers already…cancer is the uncontrolled growth of normal body processes, which can be triggered by environmental factors (such as smoking, drinking, radiation, etc), but you can also be genetically predisposed to certain illnesses (such as breast cancer).
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