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		How our cells turn dangerous
(Avoiding cancers)
To keep your body working at its best, it has a 
		sort of ‘planned maintenance’ so that older cells die off and are 
		replaced before they wear out and cause problems. Every second of your 
		life, millions of your cells die in an ordered way and new ones take 
		their place. You are probably aware of this happening in your skin, but 
		the same process happens to virtually every other cell too.
Very occasionally a single cell can be altered – 
		perhaps by chemicals, infections, radiation or even sunlight – so that 
		it won’t die when it is supposed to. When this cell forms new cells, 
		they too won’t die. Nor will the cells they create... nor the ones these 
		create in their turn. This is essentially what cancer is.
How cancer develops
At first the cancer may be localised to a few cells, 
		and sometimes it never spreads beyond this stage. But sometimes the 
		number of cells just keeps doubling. Even if your body’s defences manage 
		to kill a few of these cells, it’s not too long before there’s a 
		sizeable cancer. It’s made worse by any local inflammation, and even by 
		your body unwittingly creating new blood vessels that feed the cancer.
If a cancer is detected early when it’s still in one place, there’s a good chance it can be removed.
But once it gets 
		larger and starts to invade the surrounding area and gets into the blood 
		and lymph vessels it spreads widely and can cause damage around the 
		body. Unfortunately, cancers often don’t cause symptoms until they are 
		big enough to press on nearby structures, or have spread to critical 
		parts of the body. 
Some of the things you can do
		Tobacco smoke is particularly bad. The 
		cancer-causing chemicals it contains are carried around the whole body. 
		Smokers suffer higher levels of all types of cancer.
Follow safety instructions to avoid contact with 
		harmful substances and chemicals. 
Cover up in strong sunlight, and use sunscreen.
Try to avoid radiation, such as unnecessary 
		x-rays.
Girls should be immunised against HPV, a virus 
		that can cause cervical cancer.
Keep physically active. This seems to protect 
		against cancer in general.
It’s vital that cancer is detected early. If you 
		experience unexplained symptoms, see a doctor. There are screening 
		programmes available for some people, e.g. for breast cancer. 
What the book covers
		As well as explaining cancer in more depth, the 
		book lists steps to take so you are less likely to get any form of 
		cancer. 
It then discusses each of the main types of cancer – lung cancer, breast cancer, skin cancer etc – in turn, suggesting
steps to avoid them
how likely you are to get them
what warning signs to look out for
what screening is available
what the treatment would be.
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Selected references for the book
		