['Tumor stroma is similar to the connective tissue of chronic inflammation. The extracellular matrix of tumors is formed by cancer-associated fibroblasts that also modulate the inflammatory response.', 'We studied the ability of oral keratinocytes (NOK) and oral squamous cell carcinoma cells (SCC) to induce an innate immune response in fibroblasts. Co-cultures with fibroblasts in collagen gels and keratinocytes in inserts were used. Pentraxin 3 (PTX3) was used as an indicator of an innate immune response.', 'SCC and NOK up-regulated fibroblast mRNA expression and protein release of PTX3. mRNA levels were more pronounced in cultures with malignant cells. The induction of PTX3 was abrogated by an interleukin-1 receptor antagonist'] Do normal Oral Keratinocytes and Head and Neck Squamous Carcinoma Cells Induce an Innate Response of Fibroblasts?