CancerSpec 4.2.2.7
In short
Cancer is the result of changes in cells that lead to uncontrolled growth and division, forming a tumour. Benign tumours are contained in one area, usually within a membrane, and do not invade other parts of the body. Malignant tumours are cancers: they invade neighbouring tissues and spread in the blood to form secondary tumours.
You need to be able to describe cancer as the result of changes in cells that lead to uncontrolled growth and division. These cells can form a lump called a tumour.
| Benign tumour | Malignant tumour | |
|---|---|---|
| Cells | Growths of abnormal cells | Cancer cells |
| Where they are | Contained in one area, usually within a membrane | Invade neighbouring tissues |
| Spread | Do not invade other parts of the body | Spread to different parts of the body in the blood, where they form secondary tumours |
| Cancer? | No | Yes |
Scientists have identified lifestyle risk factors for various types of cancer, such as smoking, obesity and drinking alcohol. There are also genetic risk factors for some cancers. Viruses living in cells can also trigger some cancers.
Only malignant tumours are cancers. Say that malignant cells spread ‘in the blood’ to form secondary tumours.
Quick check
Which enzyme breaks down proteins, and what are the products?
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Protease. It breaks proteins into amino acids.
Which ventricle pumps blood around the body?
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The left ventricle.
Name the three types of blood vessel.
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Arteries, veins and capillaries.
What does bile do?
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It neutralises stomach acid and emulsifies fat, increasing its surface area.
How do malignant tumours spread?
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Cells invade neighbouring tissues and spread in the blood to form secondary tumours.
Written and checked against the AQA GCSE Combined Science (8464) specification · Updated October 2026