The Tumor Stroma: Key Component of Solid Tumors

Inflammatory cells recruit to the site of the injury due to secretion of chemo-attractants during the normal wound healing process. These inflammatory cells, once recruited, produce an abundant amount of growth factors and cytokines which in turn activate the local fibroblasts. The terms “tumor microenvironment” and “tumor stroma” are commonly used by researchers in the field. To clarify, the tumor stroma is the non-neoplastic part of the tumor microenvironment composed of various cell types such as cancer-associated fibroblasts, vascular cells, and different immune cells. The tumor stroma has been recognized as a key therapeutic target for the development of anti-cancer treatments, as it affects many hallmarks of cancer. In the last decade, the tumor stroma has been proposed to play a crucial role in many tumor-associated mechanisms such as tumorigenesis, neoplastic cell proliferation, metabolism, angiogenesis, metastasis, and immune cell infiltration.