CD8A and invasive breast carcinoma: Multivariate Cox regression analysis adjusted for tumor stage [33], histological grade [34], and lymphovascular invasion [35], which are established prognostic markers in invasive breast cancer, revealed that CD8 + [hazard ratio (HR) = 0.607; 95% confidence interval (CI) 0.404–0.911; p = 0.016] and CD8 + TCF1 + (HR = 0.401; 95% CI 0.193–0.833; p = 0.014) tumor-infiltrating cells per HPF as well as CD8 + Ki67 + / CD8 + (HR = 0.429; 95% CI 0.219–0.838; p = 0.013) and CD8 + TCF1 + / CD8 + (HR = 1.805; 95% CI 1.084–3.006; p = 0.023) are independent prognostic biomarkers linked with DFS (Table 2).