Abstract
BACKGROUND: Tumour-infiltrating lymphocytes (TILs) represent a robust biological prognostic biomarker in triple-negative breast cancer (TNBC); however, the contribution of different subsets of immune cells is unclear. We investigated the prognostic value of immune markers, including stromal TILs (sTILs), CD8(+)T and FOPX3(+)T cells, PD-1 and PD-L1 in non-metastatic TNBC. METHODS: In total, 259 patients with Stage I-III TNBC were reviewed. The density of sTILs along with the presence of total (t), stromal (s), and intratumoral (i) CD8(+)T cells and FOPX3(+)T cells were evaluated by haematoxylin and eosin and immunohistochemical staining. Immunohistochemical staining of PD-1, PD-L1 was also conducted. RESULTS: All immune markers were positively correlated with each other (P < 0.05). In the multivariate analysis, sTILs (P = 0.046), tCD8(+)T cells (P = 0.024), iCD8(+)T cells (P = 0.050) and PD-1 (P = 0.039) were identified as independent prognostic factors for disease-free survival (DFS). Further analysis showed that tCD8(+)T cells (P = 0.026), iCD8(+)T cells (P = 0.017) and PD-1 (P = 0.037) increased the prognostic value for DFS beyond that of the classic clinicopathological factors and sTILs. CONCLUSIONS: In addition to sTILs, inclusion of tCD8(+)T, iCD8(+)T cells, or PD-1 may further refine the prognostic model for non-metastatic TNBC beyond that including classical factors alone.