[The pattern recognition receptor-mediated immune tolerance is involved in tumor metastasis]

The interaction of tumor cells with host cells undergoes a progress of immunoediting, including surveillance, equilibrium and escape. The capability of escape from immune-surveillance is a hall marker of tumor cells, which greatly contributes to the tumor growth out of control and the therapy failure in tumor metastasis. It is indicated that tumor cells can recruit amounts of immune cells to tumor site and establish a suppressive immune microenvironment leading to tumor escape. The critical factor for tumor immunotolerance is the establishment of immunosuppressive microenvironment by interaction between pattern recognition receptors with pathogen-associated molecular patterns and damage-associated molecular patterns released from tumor tissue. Therefore, targeting tumor immunotolerance using small molecules or immunostimulatory biological agents such as monoclonal antibody, can inhibit tumor growth and invasion, and subsequently attenuate the tumor metastasis and decrease cancer-caused death.