RESUMEN
The communication between tumor stromal and parenchymal cells provides an insight to tumor progression. One of the main elements of the stroma, a major contributor to the extracellular environment of tumors, is carcinoma-associated fibroblasts. They can originate from either normal fibroblasts in the immediate vicinity of the tumor or from circulating bone marrow-derived mesenchymal stem cells. These myofibroblasts can arise locally from an endothelial-mesenchymal transformation at the invasive edge of the cancer and are physically associated with carcinoma cells, that is, in the development of high-grade malignancies and poor prognosis. These carcinoma-associated fibroblasts feed the epithelial tumor cells in a host-parasite relationship establishing its role in head and neck squamous cell carcinoma progression.