Preneoplastic antigen as a marker for endoplasmic reticulum of putative premalignant hepatocytes during liver carcinogenesis
Lin, J.C.; Hiasa, Y.; Farber, E.
Cancer Research 37(7 Pt 1): 1972-1981
1977
ISSN/ISBN: 0008-5472 PMID: 193631 Document Number: 115672
Further study of the subcellular localization of a prenoplastic antigen in hyperplastic liver nodules and primary hepatocellular carcinoma induced in rats by acetylaminofluorene was pursued. Antisera against 4 subcellular fractions, cytosol, smooth and rough endoplasmic reticulum and free polysomes, were obtained in rabbits and were used to assay for the presence of the antigen by immunodiffusion. The preneoplastic antigen, antigen 1, appearing as a sharp precipitin line, is located predominantly, if not exclusively, in the smooth endoplasmic reticulum fraction of hyperplastic nodules and hepatomas. It appears about .apprx. 3 wk of 2-acetylaminofluorene feeding and persists throughout the carcinogenic process in nodules and hepatomas. A 2nd antigen, antigen 2, appears in the smooth endoplasmic reticulum of nodules after 13 wk of 2-acetylaminofluorene feeding but gradually disappears on discontinuation of exposure to the carcinogen after 20 wk. This antigen, appearing as a more diffuse precipitin line, becomes demonstrable in rough endoplasmic reticulum as well but only after stripping off the ribosomes. The presence and distribution of preneoplastic antigen during carcinogenesis are revealed by immunodiffusion was similar when a more sensitive assay, microcomplement fixation, was used. The preneoplastic antigen appears to be a potentially useful marker for alterations in the smooth endoplasmic reticulum that may be related to the development of liver cancer.