Fibronectin patterns in hepatocellular carcinoma and its clinical significance

Fibronectin, a high molecular weight glycoprotein component of the extracellular matrix, was localized extracellularly and intracellularly in the nuclei and the cytoplasm of hepatocellular carcinomas (HCC) by the use of the biotin-avidin method on paraffin-embedded, pepsin-treated tissue. The specificity of the staining was confirmed by absorbing the antibodies with purified fibronectin. Twenty HCC were investigated (7 were autopsy specimens and 13 biopsy and surgical specimens). The fibronectin was either increased or decreased. When increased the fibronectin consisted of thin or thick feathery strands and was either pericellular, sinusoidal, periglandular, or stromal. Marked increase of fibronectin was seen in fibrolamellar HCC, clear cell HCC, and encapsulated HCC, correlating with the better prognosis. Decreased fibronectin was seen in two undifferentiated HCC. HCC obtained at autopsy displayed nuclear and cytoplasmic fibronectin staining. Nuclear fibronectin may be an expression of the DNA binding ability of fibronectin which becomes demonstrable in cells with increased membrane permeability.