FOXP3 and neoplasm: We compared CD69 expression on MCA-tumor-derived Foxp3− and Foxp3+ CD4+ T cells and found a striking difference in that the proportion of Foxp3+ CD4+ T cells (mean of 35.4% ± 7.0 SEM) was at least double that of Foxp3− CD4+ cells (mean of 13.1% ± 3.0 SEM) (Figure 4A).