[Escape Strategies of Tumors from Immune Surveillence]

Immune system must be able to protect us from foreign dangerous pathogens, but on the other side, it must be able to recognize our own tissues and organs. Activity of the immune system is affected by many positive (stimulatory) and negative (inhibitory) signals. Some of these negative receptors protect us from damage of our tissues at a place of inflammation as it blocks too intensive or longlasting immune reaction. Thereby, they have a physiological protective function against strong inflammatory reaction and possible subsequent autoimmune pathology. However, some of these mechanisms are also utilized by tumors to avoid immune recognition and attention of the immune cells. Other tumor escape mechanisms involve increased production of cytokines and factors which are responsible for immunosuppressive tumor microenvironment where effective immune response is actively blocked. This review summarizes the most frequently used strategies, which are utilized by tumors to avoid immune recognition and/ or killing by the immune cells.