CD4 and breast carcinoma: When purified CD4+ T cells were cultured in the presence of cell-free breast cancer cell (MCF-7) supernatants (Fig. 1A), a situation mimicking the tumor-bearing condition in which tumor-shed mediators influence the circulating CD4+ T cell repertoire, increase in the percent of dead CD4+ T cell (43.2%) in comparison to control (7.2%) was recorded.