The critical role of tumor microenvironment in cancer evolution and metastasis

Abstract

Tumor microenvironment (TME) is the indispensable module that hosts the tumor and fuels the development of cancer, the reason of death of nearly 8.8 million people in the year 2015. It is the source of nutrients and nurturing environment that supports tumor growth, progression as well as metastasis. TME acts as the platform to escape immune response by cancer cells and contribute towards drug resistance. Therefore, TME has become the immense interest of researchers across the world in order to develop novel anticancer agents, especially in terms of manipulation of its components. TME plays a key role cancer initiation, invasion, angiogenesis, metastasis, dysfunction of immune response and drug resistance and the importance of studying its components one-at-a-time cannot be stressed enough.The purpose of this review is to (1) delineate the role of various components of TME including extracellular matrix, cancer associated fibroblasts, tumor associated macrophages, tumor associated neutrophils, myeloid derived suppressor cells, natural killer cells, dendritic cells, B lymphocytes, T lymphocytes, pericytes and adipocytes and relate it to cancer pathogenesis, (2) outline the rolesof these components in cancer evolution starting from initiation to metastasis (3) and discuss some recent strategies for the continued developmentof anticancer agents. Furthermore, recent identifications of novel therapeutic targets as well as new pharmacological intervention strategies will also be discussed accordingly.