[The immunochemical demonstration of high-molecular proteins in the nuclear matrix of tumor cells]

For characterization of a high molecular-weight protein group prevailing in the tumor nuclear matrix, monoclonal antibodies to MAP-like protein p260 and to fibronectin were used. Immunoperoxidase reaction in Western blots of nuclear matrix electrophoregrams revealed protein p260 both in normal liver and hepatomas 27 and 22a while fibronectin was found in hepatomas, but absent in the normal liver. Immunoelectron microscopy with gold-conjugated antibodies showed p260 to be uniformly spread in the nuclei while fibronectin was localized mostly at the periphery of the tumour nuclei.