Cancer is the leading cause of mortality in our country, and ovarian cancer becomes a more and more important disease gradually in the field of gynecologic malignancies. According to the statistics of the Department of Health, the incidence of ovarian cancer increased in recent years and the mortality rate was the highest among all gynecologic malignancies in Taiwan. Early diagnosis for ovarian cancer is difficult due to the lack of obvious and specific initial symptoms. Therefore, it is usually at advanced stage when the diagnosis is confirmed. The prognostic parameters for ovarian cancer include tumor stage, histological subtype and grade, residual tumor after surgical intervention and the response to chemotherapy. However, the possible mechanism of ovarian cancer is still not clear now, which has considerable influence on the management and prognosis of the patients.

Malignancy is considered as a multi-factorial disease, and the influence of immunologic mechanism on progression and prognosis of cancer is more and more important. The natural CD25+CD4+ regulatory T cells actively suppress pathologic and physiological immune response, contributing to the maintenance of immunological self-tolerance and immune homeostasis. The development and function of regulatory T cells depend on the expression of the transcription factor forkhead box P3 (FOXP3). The mechanisms of suppression are still not known well. Whatever the mechanisms of suppression are, it is necessary to control the magnitude of regulatory T cells-mediated suppression for the benefit of the host because too much suppression might lead to immunosuppression and render the host susceptible to infection and cancer. We will collect the tumor tissue, ascites and peripheral blood during operation. Through this research we will set up the immunological profiles in the changes of lymphocytes, humoral immunity and cell-mediated immunity in ovarian cancer patients. The kinetic changes and associations between regulatory T cells and the severity and progression of disease will also be evaluated. Therefore, the role of regulatory T cells would be defined in the patients with ovarian cancer. We will also correlate the regulatory T cells with the clinical prognosis of ovarian cancer patients. Finally, we will try to find an efficient therapeutic strategy for the cancer patients.