What is the tumor microenvironment and why is it important to tumor development?

The tumor microenvironment is a complex and multifaceted network of interactions between different cell types and non-cellular components surrounding the tumor. It consists of fibroblasts, activated fibroblasts, immune cells, endothelial cells, components of the extracellular matrix, soluble factors, pH, etc. Collectively, these factors play a significant role in affecting the outcome of the malignancy.

Reciprocal communication between cells and their microenvironment is equally important for normal tissue homeostasis and tumor growth. Many studies have shown how bidirectional communication is mediated by cell-to-cell interactions or soluble factors. More recently, the importance of this cross-talk along with miRNA’s, metabolites and exosomes relative to cancer progression has been highlighted.