Positive E-cadherin, i.e. positive mouse anti-human E-cadherin monoclonal antibody, is one of the indicators in immunohistochemical examination of pathological specimens of malignant solid tumors such as breast cancer and prostate cancer. After the pathological diagnosis of malignant tumor patients is clear, further immunohistochemical examination is needed to clarify the severity of the disease and assess the prognosis, and the items of immunohistochemical examination include many items such as E-cadherin, Ki67, CK, ER, PR, C-erbB-2, P53, and SMA, etc. Among them, E-cadherin positivity is an indicator for the immunohistochemical examination of malignant solid tumor specimens such as breast cancer and prostate cancer. Among them, E-cadherin positivity suggests that the tumor is less malignant and has a better prognosis. However, E-cadherin alone cannot be used to determine the prognosis and severity of the disease, but should be analyzed together with other indicators, for example, p53 mutation is an indicator of poor prognosis. It is recommended that the patient should go to the oncology department in time, and the specialist should evaluate the prognosis and severity of the disease according to the patient’s pathology, immunohistochemistry results and tumor stage, and formulate a treatment plan.