There is no exact value that says how much Ki-67 is needed for chemotherapy because Ki-67 is not completely consistent in its clinical significance in different types of cancer. There are so many factors that determine the need for chemotherapy, and Ki-67 is only one of them, and a less important one at that. Ki-67 is a protein called nuclear proliferation antigen, which is essentially a protein localized in the nucleus of cells and is very closely related to the cell division cycle. In different tumor types, whether chemotherapy is needed or not has different meanings. In the case of breast cancer, Ki-67 is more closely related to chemotherapy, and if Ki-67 is greater than 15%, some doctors will advise patients to consider chemotherapy. Similarly in neuroendocrine tumors, if the Ki-67 grade is relatively high and can be greater than 30%, it is important to consider that chemotherapy can be administered, even if it is early. In colon cancer, the index Ki-67 is not as closely associated with chemotherapy. There are other tumors that are judged based on a combination of many other factors. The specific ones should be decided by the clinician according to the actual situation of the patient, the type of pathology, and the characteristics of molecular pathology.