Rabbit Anti-Human Ki-67 monoclonal antibody for ChIP, FC, ICC, IF. Ki-67 is a nuclear protein that is expressed during various stages in the cell cycle, particularly during late G1, S, G2, and M phases. The protein has a forkhead associated domain (FHA) through which it associates with the euchromatin at the perichromosomal layer with centromeric heterochromatin, and with 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.