According to the statuses of ER, PR, HER2 and Ki67, all breast carcinomas were classified into four subtypes: ER-positive with a low proliferative index (Ki67 < 14 %), ER-positive with a moderate to high proliferative index (Ki67 ≥ 14 %), HER2 positive, and triple-negative. This evidence concerns the gene MKI67 and breast carcinoma.