Prognostic impact on FOXP3 expression in triple-negative breast cancer (TNBC).

1089 Background: TNBC, one of the most aggressive breast cancer subtypes, is of pivotal clinical importance given the lack of therapeutic target. Regulatory T cells (Tregs) including FOXP3 are potent mediators of dominant self tolerance for cancer. However, obscurity as to the identity, stability and suppressive function of Tregs has impeded therapeutic use. Some of TNBCs are thought to be related with immune genes. Interestingly, TNBCs were reported to be associated with higher number of FOXP3 (Bohling et al. Mod Pathol 2008). The aim of this study is to investigate the prognostic significance of FOXP3 in TNBC. Methods: We investigated the number of tumor-infiltrating FOXP3(+) Tregs in formalin-fixed TNBC specimens which patients received palliative treatment in Samsung Medical Center between 1999 and 2007. Immunohistochemistry was used to assess the numbers of CD4(+), CD25(+), and FOXP3(+) Tregs in tumors and normal breast tissues from 86 patients. The number of FOXP3(+) Tregs was calculated as the tota...