Human epidermal growth factor receptor-2 (HER-2/neu) is a genetic
protein that is in part responsible for how certain cancer cells grow, divide,
and repair themselves. Some women have cells with more than the normal two
copies of the gene (HER-2) that produces this protein, which results in breast
cancer that grows and spreads quickly and is likely to recur after
treatment.
Tests can be performed on breast cancer cells to determine whether
HER-2/neu protein is present. This information is useful when making treatment
decisions.
