ERBB2 and breast cancer: Human epidermal growth factor receptor-2 (HER2) serves as an important biomarker for molecular typing and therapeutic decisions in breast cancer, although anti-HER2-targeted therapeutic agents can significantly improve survival of HER2-positive breast cancer patients, but HER2-positive rates in male breast cancer patients are not only lower than those in female breast cancer, but also more severe at diagnosis and have a worse prognosis [7].