Distribution of fibronectin and laminin in human liver tumors.

Two extracellular matrix and basement-membrane components, fibronectin (Fn) and laminin, were studied by the indirect immunoperoxidase technique in ten primary human liver cancers. Similar distributions of both Fn and laminin were detected in the well differentiated hepatocellular carcinomas with trabecular and tubular pattern. Two moderately differentiated hepatomas contained Fn only. Neither Fn nor laminin were present, however, in the parenchyma of one poorly differentiated hepatoma. In three cases of cholangiocarcinoma, laminin surrounded the tumorous ducts, while Fn appeared mainly in the reactive connective tissue stroma. The present findings indicate that bile-duct cancers synthesize laminin, and not Fn while differentiated hepatocellular carcinomas produce both Fn and laminin in vivo. The presence of Fn even in moderately differentiated types of liver cancer is in contrast to the findings for carcinomas developing from other organs and it may serve as a marker for primary hepatocellular carcinomas in the differential diagnosis.