Ki-67

Ki-67 is a nuclear protein associated with cellular proliferation and rRNA transcription. It is predominantly expressed during active phases of the cell cycle, such as G1, S, G2, and M phases, while absent in resting or quiescent cells. Ki-67 is widely used as a marker for cellular proliferation due to its high specificity and correlation with the growth fraction of cells, making it a valuable tool in various fields of cell biology, including developmental biology, stem cell research, and cancer studies.