Alteration of peripheral lymphocyte subsets and NK cells with tumor progression. T lymphocyte subpopulations were quantitated by flow cytometry. Samples were prepared by adding 5 μl of fluorescent monoclonal antibody of CD3, CD4, CD8 and CD161a to 100 μl of heparinized whole blood. CD3+CD4+ (T helper cell) and CD3+CD8+ (T suppressor cells) were measured and natural killer (NK) was recognized as CD3-CD161a+. Values (except for CD4+/CD8+) represent percentage (%). Data are expressed as averages and SD. * means compared with control group, P < 0.05. # means compared with group A, P < 0.05. $ means compared with group B, P < 0.05.