As it has become clear that human MDSC play an important role in the immunosuppression of advanced cancer, various strategies systemically targeting MDSC have been widely developed via elimination, functional inactivation or maturation of MDSC though their efficacy remains to be improved [8]; with regard to OC, however, the efficacy could be optimized by using local delivery of MDSC-targeting agents such as STAT3 or IL-6 blockers into peritoneum thus enhancing the therapeutic efficacy of other OC modalities, which should be evaluated in future clinical trials. Here, STAT3 is linked to cancer.