Chapter 2: Introduction to the Tumor Microenvironment

The tumor microenvironment (TME) is conceived as a dynamic interaction arena in which cancer cells interact with resident and recruited host cells, with their secreted factors and with the extracellular matrix (ECM). Moreover, non-cancerous cells in the TME interact with each other. The outcome of these multidirectional interactions is an ever-changing milieu in which the interaction partners acquire plasticity, altered phenotypes and signaling pathways. These TME events regulate, either positively or negatively, tumor survival, propagation and progression by a variety of mechanisms. It is up to the TME community to conceive and create novel means and technologies in order to target microenvironmental factors that impact, positively or negatively, tumor progression.