Due to the importance of proliferative markers in the prediction of prognosis of breast cancers, as well as a clinical need for effective targeted therapies (especially for those with more aggressive phenotypes), and based on the reports of a previous study [17], we selected the MCM family protein six (MCM6) and compared it with the Ki-67 scores regarding associations with the histologic types, molecular subtypes, and biomarker status of breast cancer. This evidence concerns the gene MKI67 and breast carcinoma.