IMMUNOLOGICAL PARALLELS BETWEEN PREGNANCY AND CANCER
Mechanisms of immunological tolerance providing the normal semi-allogeneic fetus pregnancy are also induced under conditions of cancer development and progression contributing to the growth of malignant tumor and avoiding the control by the host immune system. The presence of appropriate microenvironment, which is formed by trophoblast in the first case and under the influence of a tumor in the second case, ensures angiogenesis and protection from destructive immune responses. Interaction of the maternal immune system with the fetus is a complex process, in which the immune system is active and functions to create the appropriate conditions for successful pregnancy. Nearly the same trend is observed in malignant processes, where immune system ensures tumor cell survival and progression. At the late stages of pregnancy up to partum the activation of Th1 type immune response and expression of acute inflammation-associated genes is observed, that provides physiological rejection of the fetus. In contrast, all attributes of Th2 type immune response and chronic inflammation remain in patients with progressive cancer. Identification of the tolerance formation mechanisms and subsequent conditions for allograft fetus rejection at the end of pregnancy as well as the study of miscarriage molecular pathogenesis seem to be promising for the development of novel approaches to cancer treatment including immune therapy.