Prognostic significance of the epithelial basement membrane in laryngeal carcinomas

Background. The integrity of the epithelial basement membrane (BM) is an essential criterium for the biological behavior of tumors. Previous studies on various types of carcinomas demonstrated a good correlation between the amount of retained BM and the course of tumor growth. We therefore evaluated the prognostical significance of the tumor BM in laryngeal carcinomas. Methods. We analysed 66 cases of laryngeal carcinomas using immunohistochemistry for the visualization of the major BM components collagens IV and VII, laminin, heparan sulfate proteoglycan (HSPG) and fibronectin. The extent of BM was quantified morphometrically. A subsequent statistical analysis correlated the immunohistochemical findings with clinical parameters. Results. We observed a correlation between the degree of tumor cell differentiation and the amount of BM material retained. The loss of BM, however, affected the various components differently with an ''early'' loss of collagen VII. In non-infiltrative dysplastic lesions focal BM disruptions were seen which affected the various BM components very similarly. Statistically, collagen VII represents a marker for ''early'' stroma invasion. It also positively correlated with tumor size/stage, presence of lymph node metastasis and the recurrence of tumor growth. The collagen IV expression was positively correlated with the degree of tumor cell differentiation. The other parameters did not show further prognostically relevant data. Conclusions. Our observations provide evidence that the amount of BM and its individual components may provide significant information on the biological course of the disease. Thus, collagen VII may be a marker for ''early'' invasive tumor growth, as well as for lymphatic metastasis and local tumor recurrence, while the amount of collagen VII provides information on the tumor cell differentiation.