Ki-67: role in diagnosis, prognosis and follow-up after treatment of breast cancers

To evaluate the literature data about diagnostic value, prognosis value and interest in follow-up of Ki-67 antibody after treatment for breast cancer. We performed a literature search in pubmed using the keywords : Ki-67, anti-Ki-67, breast cancer, prognosis, proliferation, chemotherapy, hormone therapy. Ki-67 is routinely used as a static marker of proliferative activity and in follow-up-monitoring before and after treatment by chemotherapy and more recently hormonotherapy. Ki-67 was also used at a cut-off of 14% to differentiate between luminal A and B breast cancers. A high Ki-67 expression is probably related to a poorer prognosis but also a better response to neoadjuvant chemo and/or targeted therapy. More recently, genomic analysis is more reliable to classify the molecular breast cancer subtypes avoiding the possible cases of discordant Ki-67 rate. Ki-67 is also interesting in predicting histological response to neoadjuvant chemo and hormone therapy. Ki-67 evaluated by immunohistochemistry is important in routine in countries without bimolecular plateforms despite technical insufficiencies. When available, genomic grading is better to classify molecular subtypes and determine breast cancer prognosis in adjuvant and neoadjuvant setting.