Infiltration of intratumoral T cells and regulatory T cells are associated with p53 expression and ER status in early breast cancer: a Korean breast cancer study.

CTRC-AACR San Antonio Breast Cancer Symposium: 2008 Abstracts Abstract #5049 Background: Immune responses, such as rich lymphocyte infiltrate, have shown associated with improved clinical outcomes in patients with breast cancer. Recently, number of tumor-infiltrating regulatory T cell has been identified as a poor prognostic marker. There is, however, not enough data evaluating the associations between the clinicopathologic factors and quantity or quality of TILs in Asian breast cancer patients. Material and methods: CD4-, CD8-, and Foxp3-positive tumor-infiltrating lymphocytes (TILs) were detected by immunohistochemistry using the paraffin-embedded samples from the 40 patients with early stage (I-III) breast cancer. Expression status of ER, PR, HER-2, p53, and Ki-67 were also evaluated by immunohistochemistry. Clinical data, such as pathologic stage, patient's age, were available for statistical analysis. Results: Statistically significant correlation between ER expression and CD8/CD4 ratio of the TILs (Spearman r=0.447, p=0.024) was observed. Other clinicopathlogical factors, such as PR, tumor size, nodal metastasis, tumor grade, did not show significant correlation with ratio of the TILs. Additionally, tumors with more dense accumulation of p53 protein were associated with recruitment of higher number of Foxp3-positive regulatory T cells (Spearman r=0.52, p=0.0002). Ki-67, a proliferation index of the tumor cells, was also statistically significantly associated with infiltration of regulatory T cells (Spearman r=0.46, p=0.019). Discussion: Our data showed that ER-positive tumors had higher ratio of CD8/CD4 TILs, which is opposite result from the previous studies. In addition, p53 overexpression and high proliferation index of the breast cancer were associated with high regulatory T cell infiltration, but not with total TIL. The role of the p53 overexpression of the tumor cells in determining immune balance and its prognostic implication will be evaluated in the future study. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 5049.