ERBB2 and breast cancer: Luminal A breast cancer has the best prognosis and is typically treated with endocrine therapy (15); Luminal B has a good prognosis and can be treated with endocrine therapy, cytotoxic chemotherapy, or targeted therapy (16); HER2-enriched breast cancer is now commonly treated with a combination of targeted therapy and cytotoxic chemotherapy, significantly improving prognosis (17, 18); TN breast cancer remains the most aggressive subtype, primarily treated with cytotoxic (neoadjuvant) chemotherapy (19, 20).