MKI67 and breast cancer: According to the current molecular classification, breast cancers are grouped as follows: luminal A: ER+ and/or PR+, HER2- and low Ki-67 (<14%); luminal B: ER+ and/or PR+, HER2+ or HER2- and high Ki-67 (>14%); HER2+: ER-, PR- and HER2+; and basal-like (BLBC): ER-, PR-, HER2- (triple negative), plus CK 5/6+ and/or EGFR+ [72].