Purpose: To explore the correlation between tumor-infiltrating immune cell subsets and breast cancer prognosis.
Materials and methods: Specimens of 102 patients with invasive ductal carcinoma of the breast were analyzed for immune-related markers (CD8, CD20, FOXP3 and CD68). The number of positive cells in the 3 most highly stained intratumoral stroma areas of the primary tumor was counted. The mean number was calculated and used to divide patients into 2 groups for each marker (CD8-high/CD8-low, CD20-high/CD20-low, FOXP3-high/FOXP3-low, and CD68-high/CD68-low).
Results: Kaplan-Meier survival analysis showed (a) for all patients that high tumor-infiltrating CD8+ and CD20+ B lymphocytes, low tumor-infiltrating FOXP3+ regulatory T cells (Tregs), and CD68+ macrophages all increased OS and DFS (p<0.05); (b) for both the 35 ER-negative and 45 lymph-node-negative patients, high CD8+ cytotoxic T lymphocytes (CTLs) increased OS and DFS (p<0.05). Multivariate analysis of OS and DFS showed that for all patients high CD8+ CTLs and low FOXP3+ Tregs were related to good OS and DFS (p<0.05).
Conclusion: High numbers of tumor-infiltrating CD8+ and low numbers of FOXP3+ T lymphocytes both could function as potential independent prognostic markers for invasive ductal breast carcinoma.
Keywords: Immunohistochemistry; Immunoscore; Infiltrating immune cell; Invasive ductal carcinoma.