MKI67 and breast cancer: The discovery of the Ki-67 antibody by Dr. Johannes Gerdes in 1983, with the observation that Ki-67 immunohistochemical expression was only present in proliferating cells, opened the door for considerations about using Ki-67 immunohistochemical expression for the evaluation of breast cancer recurrence risk, as well as for the evaluation of how well patients with breast cancer might respond to chemotherapy.