Difference in gene expression between azo-dye-induced primary hepatomas and corresponding transplantable ascites hepatoma lines in rats.

Using RNA blot analysis, we examined the relatedness of gene expression of several rat ascites hepatoma lines (AH) to azo-dye-induced primary hepatomas (PH). Four cDNA clones previously defined as containing sequences abundantly expressed in various tumor lines showed virtually the same pattern on both RNA blots of an AH line, AH60C and of PH, thereby indicating that the tumor-abundant expression of the sequences is also well retained in PH. Expression of ras and myc oncogenes in AH was the same as that in PH. However, liver-specific mRNAs such as albumin and apoprotein A-1 mRNA were expressed in normal liver and PH, but to a much lesser extent in AH60C. alpha-Fetoprotein was expressed in PH, but little in the normal liver and, if any, very little in AH60C. alpha 2u-Globulin was not expressed in either AH60C or PH. Semiquantitative RNA dot blot analyses revealed that the different expressions of certain genes between AH60C and PH observed above also hold true, even in case of other AH lines and a solid tumor line, Morris hepatoma 5123D. Southern blot analyses of the genomic DNAs showed that the different expressions might have occurred, with no major alteration in the gene structure.