Breast cancer is cancer that starts in the breast tissue.
One in seven women in the UK will develop breast cancer in their lifetime.
Breast cancer can cause symptoms such as a lump, but a lump is not the only symptom of breast cancer.
Breast cancer starts when cells in the breast begin to divide and grow in an unusual and uncontrolled way.
Breast cancer can start in different parts of the breast.
The most common type of breast cancer starts in the ducts. The ducts are tubes in the breast that carry breast milk to the nipple.
Sometimes cancer can start in the lobules. The lobules are glands that produce milk for breastfeeding.
Breast cancer mainly affects older women.
Most breast cancers (80%) occur in women over the age of 50. And the older you are, the higher your risk.
Men can also get breast cancer, but this is rare. Most men who get breast cancer are over 60.
Breast cancer is caused by a combination of our genes, environment and lifestyles. Find out more about breast cancer causes.
The earlier breast cancer is diagnosed, the better the chance of successful treatment. So it's important to check your breasts regularly and see your GP if you notice a change.
Find out more about checking your breasts and the changes to be aware of.