Abstract: Objective To study the characteristics of peripheral blood lymphocyte subsets in patients with lung cancer, gastric cancer and breast cancer. Methods Five hundred and eight patients with cancer from the First Affiliated Hospital of Tianjin University of Traditional Chinese Medicine (256 cases with lung cancer, 152 cases with gastric cancer, 100 cases with breast cancer), and 50 healthy volunteers were collected. Two ml peripheral blood were obtained from these cases. The distribution of lymphocyte subsets in peri-pheral blood was measured by flow cytometry in these cases. The data were analyzed using SPSS 16.0 software. Results The number of lymphocytes of cancer patients was decreased, the healthy volunteers was 5 125, breast cancer patient was 3 642, gastric cancer patient was 3 178, lung cancer patient was 2 895. The case of outliers of lymphocyte subsets classified based on the three kinds of cancer was 218 (85.2%, lung cancer), 133 (87.5%, gastric cancer), 88 (88.0%, breast cancer). The case of outliers of T-lymphocyte subsets classified based on the three kinds of cancer was 83 (32.4%, lung cancer), 32 (32.0%, breast cancer), 44 (28.9%, gastric cancer). The case of outliers of CD4+/CD8+ classified based on the three kinds of cancer was 185 (72.3%, lung cancer), 108 (71.1%, gastric cancer), 84 (84.0%, breast cancer). The case of outliers of natural killerlymphocyte subsets classified based on the three kinds of cancer was 32 (12.5%, lung cancer), 22 (14.5%, gastric cancer), 16 (16.0%, breast cancer). The case of outliers of Blymphocyte subsets classified based on the three kinds of cancer was 38 (14.8%, lung cancer), 52 (34.2%, gastric cancer), 12 (12.0%, breast cancer). Compared to healthy subjects, the CD19+% of patients with lung cancer was decreased (12.8±5.0 vs. 11.5±5.7, t=3.006, P=0.003); the CD4+% of patients with gastric cancer was decreased (39.2±7.7 vs. 35.3±7.6, t=2.315, P=0.023); the CD19+% of patients with gastric cancer was decreased (12.8±5.0 vs. 8.9±4.2, t=3.302, P=0.010); the CD8+% of patients with breast cancer  was increased (24.0±8.1 vs. 29.1±13.0, t=2.019, P=0.047). Conclusion The number of lymphocytes in cancer patients is decreased, the abnormal rates of lymphocyte subsets in the three kinds of cancer patients are higher than those in healthy volunteers, the lymphocyte subsets of different kinds of cancers perform different characteristics.

Key words: Lung neoplasms, Stomach neoplasms, Breast neoplasms, Lymphocyte subsets