Breast cancer ki6740 refers to the presence of 40% positivity in the ki67 index, indicating that the patient is at risk of recurrence as well as metastasis. However, this is not absolute and the exact situation varies from person to person. Ki67 is a kind of nuclear antigen for cell proliferation, and breast cancer Ki67 test is one of the tests in pathological immunohistochemistry examination, which can reflect the proliferative activity of tumor cells as well as the degree of malignancy, and the patients can test Ki67 treatment through biopsy or postoperative specimens, so as to understand the degree of malignancy of the tumor. Generally speaking, when the Ki67 index of breast cancer is about 20%, the malignant degree of the tumor is relatively low, and the higher the value of Ki67 index, the higher the malignant degree of the tumor, and the more likely to have metastasis and recurrence. The presence of 40% positive rate of Ki6740 indicates that the degree of malignancy is relatively high, at this time the growth of the tumor is relatively fast, and if the treatment is not appropriate, it is likely to have recurrence and metastasis. Therefore, it is necessary to carry out further examination in time to have a detailed understanding of the severity of the disease, and then choose the suitable treatment plan with the help of doctors, such as surgical treatment, radiation therapy, chemotherapy and so on, and pay attention to the daily care work.