Role of the Tumor Microenvironment in Cancer Immunotherapy

In cancer, uncontrolled cell division and proliferation leads to the development of tumors. Such tumors may remain localized (benign) or may spread to other vital organs (metastatic), and accordingly, the treatment strategies vary. The benign tumors can be surgically removed or treated with radiation, but in the case of metastatic tumors, surgeries and the use of radiation are ineffective; hence in such cases, applications of chemicals or chemotherapies remain the only effective strategy to treat the malignancy. Specifically targeting the malignant tissues using specific antibodies or immunoglobulins (Ig) as nanoparticles known as nanoimmunotherapy is a recent and emerging therapeutic approach to treating different malignancies. So unlike other traditional chemotherapeutic approaches, the immunotherapeutic approach helps in boosting the body’s natural immunologic defense against cancer/tumor. The recent immunomodulatory success in treating cancers like lung and other melanoma has prompted more enthusiasm for nanoimmunotherapy and its ability to treat different malignancies. The efficacy of immunotherapy depends on the immunogenic tumor microenvironment (the ecosystem surrounding the tumor). The subject of cancer immunology today concentrates on the interactions between cancer and the host immune cells to undermine immunological tolerance. It also explains the molecular mechanism of the cytokines and chemokines in tumor progression. Here, in this book chapter, we want to review about what is known till now about the unique characteristics of tumors and its microenvironment and their influence on treatment outcomes. We have also tried to provide insights into the current various therapeutic modalities aimed at evading and suppressing tumor immunity to restore anti-tumor immunity.