Immuno-oncology: Is it a New Hope for Cancer Patients

Abstract

Cancer is the one of the leading causes of death, whose incidences is increasing day by day due to lack of understanding about its complete mechanism. Therefore, to understand complete mechanism of cancer, researchers started to move their focus from the cancer cell to the host and the environment in which the cancer grows, a very important component of which is the immune system.1,2 The immune system comprises of innate and adaptive system which provides protection to the body against pathogens. The immune cell receptors recognize the foreign and activate the complex immune response signaling pathways which results in the elimination of pathogens.3,4 The first problem with cancer cells is that they arise from our own cells, so some times unable to recognize as non self. Further, if they recognized, alters the immune response signaling pathways at various steps which results in failure of immune response. The cancer cells can avoid recognition and elimination by altering the immune response signaling pathways at various steps such as disrupting antigen recognition and presentation mechanisms, down regulates the MHC class I molecules or inhibiting the antigen processing mechanisms. Additionally, cancer cells may disrupt the pathways which are involved in controlling T-cell inhibition and activation, or by recruiting regulatory T cells (Treg) and Myeloid-derived suppressor cells (MDSC) which are immunosuppressive. Further, cancer cells may release of some of immunosuppressive immune factors such as adenosine and prostaglandin E2, and the enzyme Indoleamine 2,3-dioxygenase (IDO) which leads to progression of cancer.