What causes cancer? Part 4
Most cancers are probably due to a combination of factors
Not everybody who comes into contact with a carcinogen or has an unhealthy lifestyle will develop cancer. For example, not all smokers develop cancer of the lung. In fact, we are all probably exposed to low doses of carcinogens a lot of the time.
The body has certain mechanisms which may protect us from developing cancer. For example, it is thought that many cells which are damaged by carcinogens can repair themselves. Also, the body's immune system may be able to destroy some types of abnormal cells before they multiply into a tumour. Perhaps one carcinogen may only damage one gene, and two or more genes may need to be damaged or altered to trigger the cells to multiply 'out of control'.
In many cases it is likely that a combination of factors such as genetic make-up, exposure to a carcinogen, age, diet, the state of your immune system, etc, play a part to trigger a cell to become abnormal, and allow it to multiply 'out of control' into a cancer.
Further help and information
Cancer Research UK
Their website, Cancer Help, provides detailed facts about cancer.
© EMIS and PIP 2006 Updated: February 2006
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