The ki67 index alone cannot determine whether chemotherapy is needed. Generally, 30% positive rate may require chemotherapy, but it also depends on the size of the primary tumor lesion and whether surgery has been done to cure it. ki67 index is an index in immunohistochemistry, ranging from 0-100%, the higher the index means the more active cell proliferation, the more advanced the stage or the more malignant the cells may be. The index in immunohistochemistry is very important to determine the type and stage of tumor. In general, the treatment of malignant tumors is mainly a comprehensive treatment plan based on radical surgery, including adjuvant chemotherapy, radiotherapy, endocrine therapy and targeted drug therapy after surgery. ki67 generally guides whether radiotherapy and chemotherapy are needed after surgery, and also combines with other routine pathological examination results.