Colorectal cancer patients have more Treg cells in the PBLs than normal donors. (A) Ex vivo FACS staining of peripheral blood lymphocytes (PBLs) from a normal donor and a colorectal cancer patient. The percentage shown is that of CD25+^hi lymphocytes in the CD4+ population. (B) Percentage of Treg cells in the PBLs of colorectal cancer (n = 35) and normal patients (n = 10). (C) Percentage of CD4+ CD25+ T cells in the PBLs of patients with Dukes' A and B disease (n = 21) versus Dukes' C and D disease (n = 14).