Why don’t we get cancer every day?

On a typical day people have a coffee in the morning, walk to work, talk to friends on their mobile and even have a glass of wine with dinner.  So far today I have talked on my mobile but being ridiculously lazy on Thursdays, I have only seen the sun through glass and haven’t entered the kitchen yet!

Cancer was all over the news this week as the world health organisation (WHO) has included high mobile usage as a possible cause of cancer in their 2011 revised classifications. As I read through this list, I realised that I am regularly exposed to a variety of possible (caffeine/mobiles) and definite (UV light from the sun, alcohol) causes of cancer which lead me to the question “Why don’t we get cancer every day?”

Cancer is caused by a change in the DNA of a cell. Identical DNA is contained in the nucleus of each cell in the body and the type of cell depends on which genes in it that are switched on. Radiation, such as that released recently in Fukushima, might spring to mind when you hear about change in DNA but it can also be caused by other sources e.g. smoking, UV light. These can either directly change the DNA or they could indirectly change it by affecting one of the many vital processes that occur e.g. impairing the DNA repair process.

I had a flashback to college days when a lecturer said that a cancer cell occurs in our bodies every day but our immune system prevents it developing into a tumour. This always fascinated me as I think it embodies how amazing our body’s defence mechanisms are.

The immune system has the capability of recognising bacteria, foreign particles and cells infected by viruses. These seem obvious as it is able to tell the difference between self and non-self. However, a cancer cell is self gone wrong so how does the immune system manage to kill it? The police of our immune system include cytotoxic T cells, natural killer cells, and macrophages. They are designed to tell the difference between a normal cell and an infected/cancer cell by the composition of its surface. Once they recognise a different cell, they start a chain reaction leading to programmed cell death.

But don’t start smoking or booking sun bed sessions just yet! Cancer occurs when the immune system is overwhelmed and it overlooks a cancerous cell. This is why keeping your body in good shape can reduce your risk of cancer. Since my immune system has fought off about 9913 cancer cells so far, I think it’s time I bought it a thank you card!

8 thoughts on “Why don’t we get cancer every day?

  1. Great first post Maria. I still find it amazing that our immune system covers our collective asses so well!

  2. Very nice post. This is one of the few I’ve seen that attempts to include the concept of carcinogenesis per se into the story.

    Many studies show that acute psychological stress is associated with diminutions in immune markers, including T cells and NK cells. Although the mechanisms are extremely complex (and not properly understood), I suppose you could say that spreading scare stories about phone cancer would cause quite a lot of psychological stress for some people, thereby diminishing their immune function and exposing them to increased cancer risk. Sort of in a nothing-to-fear-but-fear-itself kind of way.

    (Of course such theories are based on an assumption of all other things being equal — which they never are!)

  3. Really interesting and well-written article, Daly. Looking forward to more!

  4. Great first post! Have just been having a bit of a freak out since the WHO came out with this info. I love that you write from a Science background but in a way that is understandable for someone like me, who is not in the least bit ‘Sciency’! Isn’t our immune system uh-maaz-ing! Keep ’em comin’! Áine

  5. Looking forward to more! Really interesting, Maria. I like the thought of giving my immune system a card and a glass of wine – reducing stress helps the immune system, right? 🙂 x

  6. 9913 cancer cells? That wouldn’t be one a day by any chance? Otherwise I’m fascinated that you have kept such close and precise tabs on what your immune system has been up to 🙂

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