The combination of histology and genomics has provided new molecular subtypes of BC in four groups: luminal A (resembling the histological phenotypes ER+, PR+, HER2− and Ki67−), luminal B (ER+, PR+, HER+/− and Ki67+), HER2 (ER−, PR− and HER2+) and triple-negative subtypes (ER−, PR−, HER2−) [47]. Here, MKI67 is linked to breast cancer.