• Question: what do you think the main cause of cancer is ??

    Asked by 10blambert to Vicky, Sara, John Robert, Gemma, Connie, Becky, Alison on 22 Jan 2014.
    • Photo: John Robert Davis

      John Robert Davis answered on 22 Jan 2014:

      This is a hard question to answer because it depends on what you mean by the cause of cancer. Cancers are formed when cells have genes mutated or corrupted that allows them to have cancer characteristics. So the main cause on a genetic scale is simply mutations.

      However every type of cancer is different, so breast cancer is different from bowel cancer which is again different from lung cancer. And not all breast cancers are the same, they can be caused due to different genes being mutated.

      Furthermore, the reasons that genes become mutated can be different. For example a common risk to skin cancer is UV light, so getting a tan. But this isn’t the same for lung cancer as no UV light can reach your lungs. There smoking is a bigger problem.
      So the complicated answer is that there is no one main cause of cancer, it can change depending on the type of cancer. That is why treating cancer is a long and difficult process that involves looking at lots of different things.

    • Photo: Vicky Forster

      Vicky Forster answered on 22 Jan 2014:


      Great question! As John has mentioned – there are hundreds of different types of cancer, it isn’t just one disease at all – so the causes of different types of cancer will be different. In some types of cancer – we are pretty confident we know what causes them, but this is never 100% accurate. For example, we think most cases of lung cancer are caused by smoking – but lots of people who don’t smoke also get lung cancer, so smoking can’t be the only cause. Similarly, if you have heard of a chemical called asbestos (which is found in old buildings sometimes, and is very dangerous), we know that breathing in the dust from this can cause a very rare form of cancer called mesothelioma. However, in most cases of cancer, we really don’t yet know what causes them – we know that things like a good diet, exercise, not smoking and minimising alcohol consumption reduces the ‘risk’ of getting cancer – but definitely can’t prevent someone from getting cancer.

      Another thing to consider is, that rarely – people are born with a faulty gene, or faulty genes which strongly increase their risk of getting certain types of cancer. An example of this is a mutation in genes called BRCA – normally BRCA genes encode proteins which help repair DNA mutations, so when this gene is faulty, people are not as good at repairing DNA mutations as people with normal BRCA are. This mutation is heritable, meaning that parents can pass down the mutation to their offspring – and it very strongly increases the risk of certain types of cancer, such as breast cancer. It isn’t the case though that this genetic mutation ’causes’ cancer – it just really, really strongly increases the risk of these people getting certain types of cancer, as they cannot repair their DNA as well as a ‘normal’ person.

      I hope this at least in part answers your question – please feel free to ask some follow up questions if you would like more information!

    • Photo: Becky Cook

      Becky Cook answered on 22 Jan 2014:

      For lung cancer, over 80% are caused by smoking, so I would argue smoking is the main cause for that cancer type.

      Genetics also plays a role as well, as some people are at more risk of cancers due to their genetic make up.

    • Photo: Gemma Swiers

      Gemma Swiers answered on 22 Jan 2014:

      I think it is also really important to point out that cancers are caused by mutation and mutation happens all the time to our genes and is caused by many different things, including naturally. Most of the time our cells are able to repair the mutation but sometimes they make a mistake and the mutation is left. A lot of the time these mutations won’t cause any harm to the cell but sometimes they might make that cell cancerous and keep on growing and dividing out of control – a cancer.

      Things like smoking are bad for us because there are chemicals in the smoke that cause mutations, so if you smoke you are increasing the amount of mutations your (lung) cells will get. If you increase the number of mutations you also increase the chance that one of those mutations will be bad for the cell and make it cancerous.