[Immunohistochemical analysis of the basement membrane expression in squamous epithelial carcinoma of the larynx].

Epithelial structures are separated from the stroma by a basement membrane (BM) which serves as a barrier for the epithelial cells. Invasive tumour growth as in laryngeal carcinoma, involves the degradation of this barrier. In our present immunohistochemical analysis, we evaluated both the quantitative and the qualitative changes in the BM composition of 50 laryngeal carcinomas. This analysis comprised the localisation of the BM components collagen IV, laminin, and fibronectin. Furthermore, we applied antibodies against BM components that have not, or only very rarely, been analysed in malignant squamous cell neoplasms--particularly collagen VII and heparan sulfate proteoglycan (HSPG). In this study we provide considerable evidence that varying amounts of preserved BM material can be found in laryngeal carcinoma of different grades of tumour differentiation. Especially by comparison of the different staining patterns for collagen IV and collagen VII, we recognised far more gaps in the staining of the BM by collagen VII than by collagen IV. This fact is underlined by the observation that even in G1 carcinomas collagen VII showed in almost 40% of the cases a complete loss of BM staining. In general, we found a correlation between the amount of preserved BM deposition and the grade of tumour differentiation. This fact may underline the significance of the immunohistochemically detectable amount of BM components as a prognostically relevant parameter.