What is Cancer?

Cancer develops when cells in a part of the body start to grow in an abnormal way. Cancer cell growth is different from normal cell growth and the cells can also invade (grow into) other tissues.

A group of cells can form a solid tumour anywhere in the body, for example in bones or the brain. Benign tumours do not spread, whereas malignant tumours can spread to other parts of the body.

Cancers of the blood called Leukaemias occur when the blood cells divide and multiply abnormally. The most common types of leukaemia in children and young people are Acute Lymphoblastic Leukaemia (ALL) and Acute Myeloid Leukaemia (AML).

When cells of the lymphatic system divide or multiply abnormally, this is called Lymphoma. This can result in lumps in the lymph glands, which are found in the neck, groin, axilla (armpit) and throughout the body.

Some cancers are classified by their grade (how abnormal or differentiated the cancer cells look microscopically) and their stage (the extent of how far the cancer cells have spread).

More Information

• What is Children's Cancer? (Cancer Research UK)

• Types of Childhood Cancer (CCLG)

• Types of Cancer (Teenage Cancer Trust)

• Cancer Types A to Z (Macmillan Cancer Support)

• Childhood leukaemia (Blood Cancer UK)