Expression And Significance Of Regulatory T Cell In Peripheral Blood Of Breast Cancer Patients

Research ContextBreast cancer is one of the most common malignancy of women. In the world, more than one million new patients are diagnosed each year. In the past few decades, the incidence of breast cancer increased year by year, and serious threat to women's health. However, the mortality rate of breast cancer has declined in recent years, partly because of the improvement of screening technology, the exaltation of surgical and radiotherapy, and the combination of chemotherapy and endocrine therapy and biological targeted therapy. If we investigate pathogenesis and prognostic factors of breast cancer in the context of immunology and molecular biology, that will help us further improve breast cancer survival rate and decrease breast cancer mortality. Regulatory T cells (Tregs) are a group of T cells which inhibits immune response function by affecting the activity of another type of cells. They have played an active and important role in the development of malignant tumors and in inhibiting tumor-specific immunity. Therefore, the action of regulatory T cells also deserves we investigate in development and prognosis of breast cancer.ObjectiveTo investigate the expressions and significance of regulatory T cells (Tregs) in peripheral blood of breast cancer patients. To analysis the differences of proportion of regulatory T cells in peripheral blood among before treatment breast cancer patients and after surgery and chemotherapy breast cancer patients and healthy controls. Comparing advantages and disadvantages of different methods to detect CD4+CD25+ regulatory T cells, and identifying best indicators and significance to discriminate regulatory T cells.MethodsSelecting 50 patients with untreated breast cancer and 50 breast cancer patients after surgery and chemotherapy and 50 healthy people, and collecting their peripheral anticoagulant blood. Flow cytometry was employed to determine the expression level both CD4+CD25+CD127-Tregs and CD4+CD25+FoxP3+Tregs. RT-PCR was employed to determine the expression level of FoxP3 mRNA.Results1. In peripheral blood of untreated breast cancer patients, the expression level of CD4+CD25+CD127- Tregs(6.34%±2.13%) was significantly higher than that of healthy people(4.89%±1.47%), the difference was statistically significant(P 0.01). In peripheral blood of breast cancer patients after surgery and chemotherapy, the expression level of CD4+CD25+CD127-Tregs(5.01%±1.46%) was not different with normal control(P=0.733).2. In peripheral blood of untreated breast cancer patients, the expression level of CD4+CD25+FoxP3+Tregs(6.26%±1.93%) was significantly higher than that of healthy people(4.8%±1.39%), the difference was statistically significant(P<0.01). In peripheral blood of breast cancer patients after surgery and chemotherapy, the expression level of CD4+CD25+FoxP3+Tregs(4.83%±1.17%) was not different with normal control(P=0.919).3. In peripheral blood of untreated breast cancer patients, the expression level of FoxP3 mRNA(0.005146±0.001464) was significantly higher than that of healthy people(0.003372±0.001079), the difference was statistically significant(P<0.01). In peripheral blood of breast cancer patients after surgery and chemotherapy, the expression level of FoxP3 mRNA (0.003482±0.001373) was not different with normal control(P=0.643).4. The expression of CD4+CD25+CD127- regulatory T cells was positively correlated with CD4+CD25+FoxP3+regulatory T cells in peripheral blood of breast cancer patients(r=0.977, P<0.01).5. The expression of CD4+CD25+CD127- regulatory T cells was positively correlated with FoxP3 mRNA in peripheral blood of breast cancer patients(r=0.927, P< 0.01).ConclusionsThe increase of proportion of regulatory T cells in Peripheral blood of breast cancer patients may cause immune escape of breast cancer, and may play an important role in the development of breast cancer.Surgery and chemotherapy may reduce the ratio of regulatory T cells in peripheral blood, and relatively enhance the anti-tumor immunity of breast cancer patients.The detection of CD4+CD25+CD 127- regulatory T cells in peripheral blood of breast cancer may be another new indicator to evaluate therapeutic effect and prognosis of breast cancer.