MKI67 and breast cancer: Numerous studies have highlighted the aggressive course of BC in YBC, characterized by a higher frequency of family history of BC, BRCA gene mutations, higher tumor grade, larger tumor size, lymph node involvement, distant metastasis at diagnosis, HR-negativity, higher Ki-67 levels, more LVI, and a higher TNBC rate, contributing to poorer outcomes [7,17,20,22,23,24,25,26].