Anti-Ki-67 (human), Rabbit Monoclonal (RM521)

Ki-67 is a nuclear protein that is expressed during various stages in the cell cycle, particularly during the late G1, S, G2, and M phases. The protein has a forkhead-associated domain (FHA) through which it associates with euchromatin at the peri chromosomal layer, the centromeric heterochromatin and the nucleolus. Ki-67 is shown to have a cell cycle-dependent topographical distribution with perinucleolar expression at G1, expression in the nuclear matrix at G2 and expression on the chromosomes during M phase. Ki-67 is commonly used as a proliferation marker because it is not detected in G0 cells, but increases steadily from G1 through mitosis. Ki-67 antibodies are useful in establishing the cell growing fraction in neoplasms. In neoplastic tissues, the prognostic value is comparable to the tritiated thymidine-labelling index. The correlation between low Ki-67 index and histologically low-grade tumors is strong. Ki-67 is routinely used as a neuronal marker of cell cycling and proliferation. In breast cancer, Ki67 identifies a high proliferative subset of patients with ER-positive breast cancer who derive greater benefit from adjuvant chemotherapy.