Hepatocellular carcinoma: expression of basement membrane glycoproteins. An immunohistochemical approach

The identification and characterization of collagenous and non-collagenous glycoproteins have made it possible to use specific antibodies as tools for the topographical localization of the various connective tissue components, and thus to follow the progression of parenchymal-stromal interactions. This investigation is an approach to the study of in vivo relationships between basement membrane components (type IV collagen, laminin) and neoplastic cells of hepatocellular carcinoma. Ten cases of hepatic carcinomas were analysed and paraffin-embedded sections were immunostained with anti-laminin and anti-type IV collagen antibodies. The avidin-biotin-peroxidase complex technique was used. In well differentiated neoplasms with hepatic tumour cells organized in a trabecular pattern lined by sinusoid structures, type IV collagen was always detected at the sinusoidal level. Laminin was evident only in two cases with a prominent intraparenchymal vascular bed. In less differentiated neoplasms, sinusoids were almost absent and only large tumour vessels were positive for both laminin and type IV collagen. At the interface between tumour tissue and the surrounding stroma, some carcinomatous elements were surrounded by laminin and type IV collagen. Our data further support the hypothesis that basement membrane phenotypic expression may be influenced both by the degree of tumour differentiation and by the characteristics of the micro-environment.