HER2+ 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 excess of the HER2 protein on their surface, leading to more aggressive tumor growth compared to other types of breast cancer. Patients with HER2+ breast cancer may benefit from targeted therapies, such as trastuzumab (commonly known as 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 managing this type of breast cancer.