The CD4/CD8 Ratio of Tumor-infiltrating Lymphocytes at the Tumor-host Interface Has Prognostic Value in Triple Negative Breast Cancer

Publication date: Available online 6 October 2017
Source:Human Pathology
Author(s): Kai Wang, Tiansheng Shen, Gene P Siegal, Shi Wei
Compelling evidence has demonstrated the prognostic value of tumor-infiltrating lymphocytes (TILs), especially in triple-negative breast cancer (TNBC). However, only a limited number of studies to investigate the importance of the subsets of T cells in TILs has been carried out, less so the significance of the location of these TILs. In this study, we explored in a cohort of 42 consecutive TNBC cases the prognostic significance of TIL subsets at the tumor-host interface (within one high power field [0.5 μm] of the invasive front) and compared them to TILs within the intratumoral stroma. Given the reported importance of TILs in HER2-overexpressing breast cancer, a subset of such tumors were also included for comparison. The range was wide in both locations, never-the-less the mean CD4⁺ and CD8⁺ T cell count was significantly higher at the tumor-host interface than that found within the intratumoral stroma (both P<.0001). The number of CD4⁺ or CD8⁺ T cells at either location was not significantly associated with distant relapse-free or overall survival. However, the CD4/CD8 ratio at the tumor-host interface was significantly associated with both relapse-free survival (hazard ratio [HR] 0.2, P=.002) and overall survival (HR 0.13, P=.002), while this association was not seen for the CD4/CD8 ratio within the intratumoral stroma. As expected, both tumor size and nodal status were significantly associated with survival outcomes. The findings further support the contention that TILs, as a marker of regional immune escape, is of prognostic importance in TNBC progression, and that the CD4/CD8 ratio of TILs at the tumor-host interface plays a distinctive role, thus appearing to be of clinical relevance.



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