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What causes cancer?

28th September 2019

Cancer is a complex disease with many different and overlapping causes. But its genetic mutations that accumulate over time in the DNA of a cell that are the real culprit.

For a cancer cell to develop, several genetic mutations need to happen. And these mutations need to happen in genes that control when, and how much, cells divide. Mutations to these genes cause cells to divide in an uncontrolled way, one of the hallmarks of cancer.

But what causes these genetic mutations?

Things inside and outside our body can cause genetic mutations. The natural processes of life generate molecules that damage DNA and cause mutations. The good news is that our cells have evolved repair kits to fix mutations and prevent cancer from developing.

Things in our environment and our lifestyle can also cause genetic mutations. UV rays from the sun can penetrate through our skin, into cells and damage DNA. Tobacco smoke contains chemicals that enter cells in our lungs and cause damage to DNA. Obesity or being overweight can cause changes in the level of hormones in our body. This can lead to cells dividing more than they should. And the more a cell divides the more it puts itself at risk of picking up genetic mutations.

Our cells can repair many of the mutations caused by these things. But continued exposure over a long period of time can cause more damage than our cells can cope with. And this is when genetic mutations emerge that can cause cancer.

Some types of cancer are also caused by infection with a virus, such as the cervical cancer virus, HPV. This virus enter cells and produces proteins that tell the cell to divide in an uncontrolled way. Thanks to research, we now have a vaccine against HPV. This vaccine has led to cervical cancer cases plummeting in countries around the world.

There are important things you can do to reduce your chances of developing cancer. Don't smoke, avoid spending too much time in the sun, and maintain a healthy weight through a balanced diet and regular exercise. But remember, everyone is different, and every cancer is different, so there is no magic bullet.