Collagen type III and type IV detection in and around human hepatocellular carcinoma

Extracellular matrix proteins participate in tumor cell growth and progression. Their role in the extratumoral liver tissue needs to be elucidated. Eight patients with hepatocellular carcinoma on noncirrhotic livers are investigated by means of light microscopical and ultrastructural immunohistochemistry for collagen type III and type IV. In the tumor collagen type III, staining is weaker, and collagen type IV is increased. It is topographically located near perisinusoidal stromal cells. In the extratumoral liver tissue, the immunostaining for the two antibodies is stronger perisinusoidally. The number of Ito cells increases significantly in the extratumoral liver tissue. A lot of transitional cells are found there. Sinusoids in the extratumoral tissue are dilated and filled with lymphoid cells and platelets. The presence of matrix proteins between tumor cells is necessary to regulate their growth and differentiation. The increase in extracellular matrix content perisinusoidally in the extratumoral tissue probably erects a protective barrier against metastasizing tumor cells. There, collagen type III and type IV accumulation is probably initiated by signals coming from tumor cells, or from inflammatory cells and platelets in sinusoids.