Phenotypic comparison of FOXP3⁺CD4 T cells in tumors versus peripheral blood in healthy donors. Tumor digests from patients and peripheral blood samples from healthy donors were thawed and immediately stained with anti-CD3, anti-CD8, and anti-FOXP3 mAb along with either (A) anti-CD25 or (B) anti–CTLA-4 mAbs. The dotplots were gated on CD3CD4 (CD3⁺CD8⁻) T cells. The numbers represent the percentages of CD4 T cells in each quadrant. These results are representative of several independent experiments using tumor digest samples (n = 26) and PBL samples from the same patients (n = 9) and healthy donors (n = 5).