The nuclear protein Ki-67 was initially identified by the monoclonal antibody Ki-67, which was generated through immunization of mice with nuclei from the L428 Hodgkin's lymphoma cell line. The Ki-67 protein plays a crucial role in ribosomal RNA transcription and cell proliferation. Its expression is detected during the G1, S, G2, and M phases of the cell cycle, while it is absent in the G0 phase. Ki-67 is strongly expressed in proliferating cells and has been reported as a prognostic marker for various types of tumors.
