Abstract: Abstract: Objective To study the effect of rotary magnetic field (RMF) combining 5-Fu on the cycle and apoptosis of mouse cell line SP2/0 in vitro. Methods SP2/0 cells were randomly divided into four groups: control group (N), 5-Fu group (C), magnetic group (M) and magnetic combining 5-Fu group (M+C).The M and M+C groups were treated with a RMF for two hours once a day.On day 4, the C and M+C groups were treated with 5-Fu 20 μg/ml.On day 5, cell cycle and apoptosis were measured by the flow cytometric (FCM). Results The S phase proportion of the M group and the G1 phase proportion of the C group were higher than that of the other three groups（P<0.05）.The S phase proportion of the M+C group decreased and lower than that of the M group，but was still higher than that of the N and C groups（P<0.05）.There was no significant difference in apoptosis rates between the N and M groups（P>0.05）.The apoptosis rates of the C and M+C groups were remarkedly higher than those of the N and M groups and the M+C group had the highest apoptosis rate. Conclusion The RMF can't induce the apoptosis.But it can enhance the cytotoxicity of 5-Fu and promote the cell apoptosis.The mechanism of the apoptosis may be related to SP2/0 cell line arrested at S phase.Objective To investigate the distribution CD4+CD25+FOXP3+ regulatory T cells (Treg), CD4+T and CD8+T cell in colorectal carcinoma microenvironment and their correlation with conventional clinico-pathological features. Methods Frozen sections and immunohistochemistry (IHC) were used to detect FOXP3+ Treg and CD4+T and CD8+T cells in fresh specimen collected from 42 patients with colorectal carcinoma.Their association with clinico-pathological features in tumor and peri-cancer tissues were evaluated. Results The expression level of FOXP3 in colorectal carcinoma was significantly higher than that in peri-cancer tissues （P<0.01）.A higher number of tumor infiltrating FOXP3+ Tregs was detected in the patient groups with poor differentiation and lymphatic metastasis as compared to that of the patient groups with well differentiation and non-lymphatic metastasis（P<0.01）.The number of Intratumoral CD4+, CD8+T cells and CD4+/CD8+ ration were lower than those in stromal tissue（P<0.01）.The ratio of Intratumoral CD4+/CD8+ at stage Ⅲ+Ⅳ and lymphatic metastasis were lower than those at stageⅠ+Ⅱ and non-lymphatic metastasis（P<0.05）.There was significant negative correlation between the number of Treg and Intratumoral CD4+/CD8+ ration（r=-0.605, P<0.01）. Conclusion The Tregs may play an important role in the tumorigenesis and development of colorectal carcinoma.A higher number of tumor infiltrating FOXP3+ Tregs in tumor and the imbalance of CD4+T and CD8+T cells may escape the immunosurveillance.