A brief glimpse of a tangled web in a small world: Tumor microenvironment

Abstract

A tumor is a result of stepwise accumulation of genetic and epigenetic alterations. This notion has deepened the understanding of cancer biology and has introduced the era of targeted therapies. On the other hand, there have been a series of attempts of using the immune system to treat tumors, dating back to ancient history, to sporadic reports of inflamed tumors undergoing spontaneous regression. This was succeeded by modern immunotherapies and immune checkpoint inhibitors. The recent breakthrough has broadened the sight to other players within tumor tissue. Tumor microenvironment is a niche or a system orchestrating reciprocal and dynamic interaction of various types of cells including tumor cells and non-cellular components. The output of this complex communication dictates the functions of the constituent elements present within it. More complicated factors are biochemical and biophysical settings unique to TME. This mini review provides a brief guide on a range of factors to consider in the TME research.

Strategies to overcome myeloid cell induced immune suppression in the tumor microenvironment

“…Local immune suppression and dysregulation are common features of cancer and are closely associated with tumor metastasis and resistance to therapy. The interaction between cancer and the host immune system is a key factor in determining tumor control or progression (1)(2)(3). Tumor infiltrating leukocytes, particularly monocytes, myeloid derived suppressor cells (MDSCs) and neutrophils create a tumor microenvironment (TME) that is inhospitable to effector cells such as CD4 and CD8 T cells and NK cells (4)(5)(6)(7)(8).…”

Editorial: Complexity of tumor microenvironment: A major culprit in cancer development, volume II

“…The tumor microenvironment (TME) consists of tumor cells along with various immune, stromal, and endothelial cells, along with extracellular matrix components ( 1 – 3 ). Notably, complex interactions and material exchanges between the tumor microenvironment and its surroundings support tumor growth and progression ( 4 , 5 ).…”

Editorial: Complexity of tumor microenvironment: A major culprit in cancer development

“…The tumor microenvironment (TME) is a complex landscape composed of intrinsic and extrinsic elements besides tumor cells including various immune cells, tumor-related stromal cells, and endothelial cells along with extracellular matrix components ( 1 – 3 ). Notably, the ability of tumor cells to invade surrounding tissues or metastasize through blood and lymphatic vessels implicitly involves cooperation with elements of the TME ( 4 – 6 ).…”