Question: why is there cancer

Bethany Dearlove answered on 16 Jun 2014:

There are lots of different types of cancer, but the thing they have in common is abnormal cell growth. Over time, most cells in our body need to make copies – for example, to allow us to grow, to replace worn out cells or to replace damaged tissues. This process is known as mitosis, and results in two identical copies of the original cell. However, sometimes the processes controlling the copying go wonky, and the copying process gets out of control. These out of control cells are cancer cells, and they continue to get copied, making more mistakes along the way. The resulting cluster of cells form the lumps that are referred to as ‘tumours’, and the cancer can spread to other parts of the body through the blood.

Really then, your question is why the processes controlling cell copying might break down – and the answer isn’t easy, as there are a number of possible reasons including age, diet, smoking, radiation, viral infections and genetic defects. Each case of cancer is different, and so there’s lots of research into the causes of cancer. You can find out more about some of them at the Cancer Research UK website: http://www.cancerresearchuk.org/cancer-info/cancerandresearch/all-about-cancer/what-is-cancer/what-causes-cancer/.