MKI67 and breast cancer: Ki67 expression was assessed by immunohistochemistry (IHC) in formalin‐fixed, paraffin embedded tumor tissue samples from T1 and T2 (Monoclonal Mouse Anti‐Human Ki‐67 Antigen, Clone MIB‐1, Dako Omnis‐Agilent) according to the manufacturer's recommendations and following the latest international recommendations for Ki67 assessment in BC (Nielsen et al., 2021).