HER2 is a protein that helps cells to grow and divide.

Some women with breast cancer have higher than normal levels of the HER2 protein. This is called ‘HER2-positive breast cancer’. About one in five people have HER2-positive breast cancer.

HER2-positive breast cancer is a more aggressive form of breast cancer than HER2-negative disease.

The pathology report shows whether a woman's breast cancer cells are HER2 positive.