Abstract: The present invention relates to a novel combination of (1) a substance that suppresses or inhibits the function of extracellular TCTP (translationally controlled tumor protein), especially released from tumor cells, and (2) a cancer immunotherapeutic agent for the treatment of cancer. Preferably, such a cancer immunotherapeutic agent is an immune checkpoint inhibitor. The substance that suppresses or inhibits the function of extracellular TCTP functions as an activator or enhancer of anti-tumor immune cells including T cells and natural killer (NK) cells and/or an antagonist of immunosuppressive cells, such as myeloid-derived suppressor cells (MDSCs), in the tumor immune microenvironment (TIME). The combination according to the present invention is useful for treating or preventing cancer. The combination according to the present invention is also useful for alleviating, reverting, or preventing immune suppression in the tumor immune microenvironment.

Abstract: The present invention is intended to identify a modulatory substance of the tumor immune microenvironment, and to provide a therapeutic utilization method of the modulatory substance. Specifically, the present invention relates to an inhibitor of the accumulation of myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment (TIME), wherein the inhibitor comprises, an active ingredient, a substance that suppresses or inhibits the function of an immunomodulator released from dead tumor cells. More specifically, the present invention relates to the aforementioned inhibitor comprising a substance that suppresses or inhibits the function of, for example, TCTP (translationally controlled tumor protein).