HER2-positive refers to a specific type of breast cancer that tests positive for the HER2 protein, which promotes the growth of cancer cells. This means that the cancer cells have an overexpression of the HER2 gene, leading to more aggressive tumor growth compared to other types of breast cancer. Patients with HER2-positive breast cancer may benefit from targeted therapies, such as trastuzumab (Herceptin), which specifically attack the HER2 protein. These treatments can improve outcomes and reduce the risk of cancer recurrence, making them an important option in the management of this type of cancer.