Ki67 positivity rate of 25% means that Ki67 positively expressing cells account for 25% of the total number of cells, and is an indicator for assessing the proliferative activity of the tumor.
Ki67 antigen is expressed in the late G1, S, M, and G2 phases, but not in the G0 phase, and has a short half-life, so it is a reliable indicator of tumor proliferative activity.
Ki67 positivity rate refers to the proportion of cells with positive Ki67 expression to the total number of tested cells after immunohistochemical examination. The higher the positive rate, the higher the proliferative activity of the tumor, the poorer the differentiation of the tumor, the higher the degree of malignancy, the easier the metastasis and recurrence, and the poorer the prognosis.
The high or low expression or negative or positive cut-off value of Ki67 is related to the type of tumor and the detection method used by the local pathological laboratory center. Generally, 20-30% positivity is considered as the high and low expression cut-off value for breast cancer, 10% as the negative and positive cut-off value for gastric and cervical cancers, and 25% as the weakly positive and moderately positive cut-off value.
Ki67 positivity rate of 25% should refer to the local hospital pathology center cut-off value for comparison and judgment, if it is low expression, it generally indicates that the tumor has a better prognosis; if it is high expression, it indicates that the prognosis is poor. Meanwhile, the positive rate is also one of the criteria for deciding whether chemotherapy is needed.
It is recommended that patients combine the reference values of local hospitals to make judgment, consult the doctor in time, and follow the doctor’s instructions to choose the appropriate treatment.