Ki-67 [SP6] is a rabbit monoclonal antibody that is intended for laboratory use in the qualitative identification of Ki-67 protein by immunohistochemistry (IHC) in formalin-fixed paraffin-embedded (FFPE) human tissues. The clinical interpretation of any staining or its absence should be complemented by morphological studies using proper controls and should be evaluated within the context of the patient’s clinical history and other diagnostic tests by a qualified pathologist. The Ki-67 nuclear antigen is associated with cell proliferation. It is found throughout the cell cycle in the G1, S, G2, and M phases; but not the (GO) phase. It is used to grade proliferation rates of tumors. The high affinity and/or binding capacity of rabbit antibodies provide superior staining results and less chance for technical false negatives.