Abstract

Regulatory T cells (T_reg), also termed suppressor T cells, control self-reactive T cells in the periphery, thereby conferring protection against immunologic self-destruction. While T_reg are essential for the prevention of autoimmunity, they also inhibit immune responses against tumor antigens. This is corroborated by an increased mortality rate associated with the presence of a high number of intratumoral T_reg. Tumor infiltration by non-T_reg, on the other hand, is predictive for a substantially longer patient survival. These clinical data suggest that ovarian cancer patients can spontaneously mount effective antitumor immune responses that are undermined by T_reg-mediated tolerization. The present article reviews clinical and experimental findings on T_reg in ovarian cancer, with special regard to potential therapeutic implications, which may result from the existing evidence.