Tumor microenvironment as a potential source of clinical biomarkers in non-small cell lung cancer: can we use enemy territory at our advantage?

The relevance of tumor microenvironment (TME) in tumorigenesis is widely known, and many efforts have been made in order to fully understand its peculiarities (1). It is acknowledged that tumor cells closely interact with TME, which is constituted by blood vessels, immune cells, fibroblasts, signaling molecules, and the extracellular matrix (ECM). On one hand, tumor cells modify the microenvironment by releasing extracellular signals, thus promoting immune tolerance and neoangiogenesis, resulting in an ecosystem that is suitable for their survival; on the other hand, the now-adapted TME promotes proliferation and survival of neoplastic cells (2,3).