CD4 and breast carcinoma: In addition to the enhanced attraction of CD4+CD25+ T cells, co-culture of CAF-S1 fibroblasts and CD4+CD25+ T cells demonstrated an increase in CD25+FOXP3+ T cells and enhanced their survival in a contact dependent manner (9) Similarly, in breast cancer, the above mentioned immunosuppressive CAF S1 subtype correlates with an increase in FOXP3+ regulatory T cells.