FOXP3 and breast cancer: Based on recent data alluding to the important role of tumor infiltrating lymphocytes (TILs) in breast cancers [24], we examined the adaptive immune response by immunostaining for CD3 (T-lymphocytes), CD 20 (B-lymphocytes) and FOX P3 (regulatory T-lymphocytes; Tregs) in C3HBA tumors (Supplementary Figure 2SA-S2C).