There are a number of types of breast cancer and some, like triple positive, are known as hormone receptor-positive cancers.
This means the tumours are encouraged to grow by hormones, such as oestrogen, progesterone and a protein called HER2, that are found naturally in the body
These cancers are much more likely to respond to drug treatments that target these hormones to help stop the cancer cells dividing and growing.
Breast cancer is the most common type of cancer affecting women in the UK according to the NHS, but it can also affect men.
More than 50,000 people in the UK are diagnosed with it each year and figures from Cancer Research, external suggest one in every seven women in the country will be diagnosed in their lifetime.
It still claims the lives of more than 11,000 British people each year, but Cancer Research says survival rates are improving, with 76% of patients living for at least 10 years after diagnosis.
