- Acute lymphoblastic leukaemia (ALL) is a rare type of cancer that affects the blood and bone marrow.
- It usually develops quickly and needs to be treated straight away.
- It's most common in children and young people, especially children aged 4 and under.
- How serious it is depends on the type of acute lymphoblastic leukaemia you have, your age and your general health.
Important: Get your symptoms checked
It's important to get any symptoms of acute lymphoblastic leukaemia checked as soon as possible.