SIGNIFICANCE OF STROMAL DESMOPLASIA AND MYOFIBROBLAST APPEARANCE AT THE INVASIVE FRONT IN SQUAMOUS CELL CARCINOMA OF THE ORAL CAVITY

Background. Tumor invasion involves complex interactions between tumor and stromal cells. We examined the extent of connective tissue in the tumor stroma and whether myofibroblasts play a role in assisting cancer invasion and metastasis. Methods. Biopsy materials from 84 patients with oral squamous cell carcinoma (SCC) were used. We compared data from intrastromal collagen fibers using Azan staining, immuno-histochemical identification of myofibroblasts by cytoskeletal markers, alpha-smooth muscle actin, vimentin, desmin, and clinicopathological parameters. Clinical outcome was compared by 5-year survival rate. Results. There were high levels of stromal collagen fibers in invasive tumors. Myofibroblast appearance increased with increasing tumor invasiveness. Lymph node metastasis occurred more frequently in the myofibroblast-positive group, and the survival rate was significantly poorer in this group. Conclusions. Fibrous stroma in SCC appeared to have a desmoplastic response. However, an independent invasive mechanism may regulate the stroma, with tumor desmoplasia occurring in highly developed, invasive tumors. (C) 2009 Wiley Periodicals, Inc. Head Neck 31: 1346-1353, 2009