Novel Therapeutic Strategies for Solid Tumor Based on Body's Intrinsic Antitumor Immune System.

The accumulation of mutated somatic cells due to the incompetency of body's immune system may lead to tumor onset. Therefore, enhancing the ability of the system to eliminate such cells should be the core of tumor therapy. The intrinsic antitumor immunity is triggered by tumor-specific antigens (TSA) or TSA-sensitized dendritic cells (DC). Once initiated, specific anti-tumor antibodies are produced and tumor-specific killer immune cells, including cytotoxic T lymphocytes (CTL), NK cells, and macrophages, are raised or induced. Several strategies may enhance antitumor action of immune system, such as supplying tumor-targeted antibody, activating T cells, enhancing the activity and tumor recognition of NK cells, promoting tumor-targeted phagocytosis of macrophages, and eliminating the immunosuppressive myeloid-derived suppressor cells (MDSCs) and Treg cells. Apart from the immune system, the removal of tumor burden still needs to be assisted by drugs, surgery or radiation. And the body's internal environment and tumor microenvironment should be improved to recover immune cell function and prevent tumor growth. Multiple microenvironment modulatory therapies may be applied, including addressing hypoxia and oxidative stress, correcting metabolic disorders, and controlling chronic inflammation. Finally, to cure tumor and prevent tumor recurrence, repairing or supporting therapy that consist of tissue repair and nutritional supplement should be applied properly.