As a result, 4,036 (42.9%) of the patients were reclassified as having luminal A–like disease and 5,379 (57.1%) were considered to have luminal B–like breast cancer (Figure 1).In order to verify whether the single modifications improved the categorization of patients in terms of outcomes, we evaluated the long-term DDFS of patients with low (<14%), intermediate (14% to 19%) and high (≥20%) Ki-67 levels, stratified according to PgR level (<20%vs. This evidence concerns the gene MKI67 and breast cancer.