CD4 and breast carcinoma: Incubation of non-regulatory CD4+ T cells with tBregs bearing high expression levels of CD40, CD80, CD86, MHC class I and II molecules, and TGF-β production capacity led to the significant generation of CD4+CD25+FOXP3+ Tregs which in turn inhibited CD8+ T cell proliferation—thereby facilitating breast cancer escape and metastasis (8).