Ki67 positivity 2+ (++) indicates moderate positivity, more active tumor proliferation, higher degree of tumor malignancy, and poorer prognosis.
Ki67 antigen is a reliable indicator of the proliferative activity of tumor cells, and a high Ki67 positivity rate indicates active proliferation of tumor cells, poor differentiation of the tumor, high malignancy, high likelihood of metastasis and recurrence, and poor prognosis.
According to the Ki67 positivity rate, it can be classified as negative (-), weak positive (+), moderate positive (++), strong positive (+++), generally negative and weak positive are low expression, moderate and strong positive are high expression.
The grading thresholds may vary according to different tumor types and pathology centers, e.g. 20-30% of ki67 for breast cancer as the value for determining high and low expression, and 25-49% of ki67 positivity for cervical and gastric cancers as (++).
Ki67 positivity ++ represents moderate positivity. Moderate positivity belongs to the high expression range, but the positive rate is lower than that of strong positivity. Moderate positivity indicates higher proliferative activity of the tumor, higher malignancy of the tumor, higher risk of recurrence and metastasis, and poorer prognosis.
It is recommended to combine the tumor type, stage, immunohistochemistry and other indicators to choose the appropriate treatment plan and follow the doctor’s instructions.