Prognostic aspects of the loss of epithelial basement membrane components in preinvasive and invasive laryngeal carcinomas.

The integrity of the epithelial basement membrane (BM) is an essential criterion or the biological behaviour of tumors. Previous studies on various types of carcinomas have demonstrated a good correlation between the amount of retained BM and the course of tumor growth. We therefore evaluated the prognostic significance of the tumor BM in laryngeal carcinomas. In this study, we analyzed 66 cases of laryngeal carcinomas using immunohistochemistry for the visualization of the major BM components collagen IV and VII, laminin-1, heparan sulfate proteoglycan (HSPG, perlecan) and fibronectin. The extent of retained BM-material was quantified morphometrically. A subsequent statistical analysis correlated the immunohistochemical findings with clinical and routine histological parameters, such as the mode of tumor infiltration. All carcinomas showed a defective epithelial BM. In addition, 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. When we statistically analyzed the correlation between the BM staining pattern and prognostically relevant parameters, collagen VII represented 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. Our observations 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 IV correlates with the tumor cell differentiation.