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 ol the biological behaviour of tumors. Previous studies on various types of carcinomas have demonstrated a good correlation betwe en the amount of retained BM and the course of tumor growth. We theref ore evaluated the prognostic significance of the tumor BM in laryngeal carcinomas. In this study, we analyzed 66 cases of laryngeal carcinom as using immunohistochemistry for the visualization of the major BM co mponents collagen IV and VII, laminin-l, heparan sulfate proteoglycan (HSPG, perlecan) and fibronectin. The extent of retained BM-material w as quantified morphometrically. A subsequent statistical analysis corr elated the immunohistochemical findings with clinical and routinehisto logical parameters, such as the mode of tumor infiltration. All carcin omas showed a defective epithelial BM. In addition, we observed a corr elation between the degree of tumor cell differentiation and the amoun t of BM material retained. The loss of BM, however, affected the vario us components differently with an ''early'' loss of collagen VII. In n on-infiltrative dysplastic lesions focal BM disruptions were seen whic h affected the various BM components very similarly. When we statistic ally analyzed the correlation between the BM staining pattern and prog nostically relevant parameters, collagen VII represented a marker for ''early'' stroma invasion. It also positively correlated with tumor si ze/stage, presence of lymph node metastasis and the recurrence of tumo r growth. The collagen IV expression was positively correlated with th e degree of tumor cell differentiation. The other parameters did not s how further prognostically relevant data. Our observations provide sig nificant information on the biological course of the disease. Thus, co llagen VII may be a marker for ''early'' invasive tumor growth, as wel l as for lymphatic metastasis and local tumor recurrence, while the am ount of collagen TV con elates with the tumor cell differentiation.