MAPT and breast cancer: To address the above questions, we considered the following potential methods and strategies for future investigation: (1) utilize positron emission tomography (PET) to monitor real-time changes in E2 or HA-E2 levels within the hippocampus and MS nucleus; (2) measure tau protein and β-amyloid levels after HA-E2 treatment; (3) conduct long-term observation of factors related to cardiovascular disease and breast cancer after HA-E2 treatment.