1.Is breast cancer prone to brain metastasis? Brain metastases originate from primary lung cancer in 30%-60% and breast cancer in 15%-25%. It can be seen that breast cancer is the second most common primary site of brain metastases after lung cancer. With the improvement of breast cancer treatment in recent years, the survival period of breast cancer patients has been significantly extended, and the incidence of brain metastases from breast cancer is also increasing. 2.What are the types of breast cancer brain metastases? In which parts of the body do they often occur? The most common type of breast cancer brain metastasis is brain parenchymal metastasis, which accounts for 85%-95%; followed by cancerous meningitis, which accounts for 5%-15%; the least common is cremaster medullary spread, which accounts for 1%. The lesions of brain parenchymal metastases from breast cancer are usually at the corticomedullary junction, i.e., the gray-white matter junction. Among them, 80% are distributed in the cerebral hemisphere, 15% in the cerebellum and 5% in the brainstem. Which breast cancers are prone to brain metastasis? Premenopausal female patients with extensive lesion invasion and hormone receptor-negative patients are prone to CNS metastasis. Specifically, young women (age <50 years), large masses (>5 cm), high histological grade of primary tumor, estrogen receptor negative, triple negative breast cancer, cytokeratin 5/6 (CK5/6) positive, human epidermal growth factor receptor (Her-2) overexpression, epidermal growth factor receptor (EGFR) high expression, existing lymph node metastasis, existing lung metastasis Brain metastases are more frequently seen.