Althobiti M, et al. - The spatial and temporal heterogeneity of tumor-infiltrating lymphocytes (TILs) in breast cancer (BC) and its association with immune cell subtypes were evaluated. For this investigation, a subset of full-face hematoxylin and eosin (H&E) stained slides were analyzed for TILs heterogeneity within primary tumors and the corresponding local recurrent carcinomas to report on spatial and temporal TILs heterogeneity. According to the findings, average TILs in one full-face H&E stained section reliably represent whole tumor TILs, in spite of the heterogeneity of immune cell type components. Researchers reported that TILs were correlated with outcome in triple negative breast cancer (TNBC) and also had prognostic significance in a recurrent tumor.