Tan AS, Yeong JPS, Lai CPT, et al. - A total of 406 triple-negative breast cancer (TNBC) cases diagnosed between 2003 and 2015 at Singapore General Hospital were included in this study by the researchers in order to quantify and localize Ki-67 expression in both epithelial and immune compartments in TNBC and examine its relationship with clinicopathological parameters and survival outcomes. A high Ki-67 labeling index (LI) > 0.3% was related to enhanced disease-free survival in a multivariate analysis adjusted for tumor size, histologic grade, age at diagnosis, and lymph node stage. A favorable prognostic marker for both disease-free survival (DFS) and overall survival was high Ki-67-positive immune cell count per tissue microarray. The combination of high Ki-67 LI and high MKI67 expression had a correlation with improved DFS and OS. Hence, this study was among the first that reflected that Ki-67 was related to favorable prognosis in an adjuvant setting in TNBC, and the multiplex immunofluorescence—based assessment of Ki-67 expression on both tumor and immune cells signified a novel prognostic strategy.