• Question: what causes cancer

    Asked by charliexx to Carla, Madgie, Nick, Vicky, Werner on 19 Nov 2013.
    • Photo: Vicky Forster

      Vicky Forster answered on 19 Nov 2013:

      Hi Charliexx,

      Good question – in short, in most cases of cancer, we aren’t yet sure. However we are quite clear on some things that cause cancer – for example smoking. Smoking causes cancer because cigarette smoke has many chemicals in it which are carcinogenic (the word we use to describe something which has a high risk of causing cancer). It’s not just lung cancer either – smoking increases your risk of lots of cancers, including leukaemias, throat cancers, mouth cancer etc. We know this because the carcinogenic chemicals damage DNA – and damaged DNA can lead to cancer if the cells DNA repair machinery does not repair it well enough.

      However in a lot of cases of cancer, the causes aren’t really well known. For example, there is a very rare type of leukaemia which only really occurs in babies – these babies are born with this type of leukaemia and we have very little idea of what causes it yet. Part of my job is trying to find out why people get leukaemia in the first place, but it is an area of cancer research which is one massive puzzle, and has lots of bits to fill in.

      Hopefully in a few years time, I will be able to answer a question similar to yours but with far more detail!

    • Photo: Werner Muller

      Werner Muller answered on 19 Nov 2013:

      Cancer is usually caused by gene mutations. The cause of the mutants can be manifold. Sometimes people carry faulty genes that control that DNA replication and DNA repair and this leads to an increase in cancer. Environmental factors can also cause DNA mutations, one of it can be UV light on skin (like excess of sun bed visits), and then lead to cancer. The immune system constantly makes sure that cells which have a potential to develop as cancer cells are removed and if the Immune system is impaired, cancer cells can start to grow. There are also infections (usually viral infections) that can cause cancer, one of which is the papilloma virus).

    • Photo: Nick Groves-Kirkby

      Nick Groves-Kirkby answered on 19 Nov 2013:

      Both great answers above.

      Some cancers also have genetic causes and run in families.

      Breast cancer is a good example. If someone inherits a faulty copy of a gene called BRCA1 they have a very high risk of developing breast or ovarian cancer during their lifetime. BRCA1 is a gene that is involved in repairing DNA. People with a faulty copy will have more damaged DNA, and a higher risk of cancer.

      This faulty BRCA1 is what Angelina Jolie discovered she had. She wasn’t guaranteed to get cancer, but she decided that she would undergo surgery to reduce her chance of developing it in the future.

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