• Learn about cancer
  • What is cancer?
    • A brief history of cancer
    • What are we made of?
    • How do cells become cancerous?
    • How does cancer make you ill?
    • How many different types of cancer are there?
  • What causes cancer?
  • Detecting cancer
  • Cancer treatment
• Cancers at a glance
• Research highlights
• About cancer research
• Understanding 'risk'
• Our history and achievements

What is cancer?

People often think of the word 'cancer' as describing a single disease with a single cause, like 'flu' or 'HIV'. This is slightly misleading. Cancer is the name given to any illness resulting from one of our body's own cells growing out of control.

There are many processes that control a cell’s growth and division, each of which can go wrong. As a general rule-of-thumb, several of these control mechanisms need to be damaged before a cell becomes cancerous.

At Cancer Research UK, one of our main aims is to work out exactly how cells grow, divide and survive. Eventually, we will understand how all cancers form and how they grow out of control, leading to improved cancer treatments and better patient care.

• A brief history of cancer
• What are we made of?
• How do cells become cancerous?
• How does cancer make you ill?
• How many different types of cancer are there?