Tumor Microenvironment and its Functions

Abstract

Tissue microenvironment is a complex system which is composed of many cell types as well as non-cellular components. It functions for structural support, tissue homeostasis maintenance and involves in the immune system. Based on the same concept, tumor microenvironment is defined as cells, vessels and molecules surrounding and influencing tumor cells. Cells residing in the tumor environments secrete several molecules including cytokines, chemokines, growth factors and protease enzymes, which play crucial roles in tumor progression and metastasis. Therefore, research nowadays demonstrates wealth information supporting that targeting specific cells and molecules in the tumor microenvironment can be beneficial for cancer therapy. Moreover, the new information demonstrates that the tumor microenvironment is related to a carcinogenesis, especially the inflammation-associated carcinogenesis. In normal situations, when cells get injured or infected, the sequence of events including acute inflammation and tissue repair occurs in discrete order and well-organizes in order to get rid of the cause of injury or infection, and then get the tissue back to normal homeostasis.  In contrast, the chaotic disorganization of inflammation and repair occurs during chronic inflammation leading to tissues fail to achieve homeostasis.  Hence, tumors are wounds that never heal.  Due to tumor microenvironment plays roles in carcinogenesis, it would be strongly considered as a target for cancer prevention. 
Key words: Tumor microenvironment, carcinogenesis, tumor progression