COMPARISON OF GLYCERALDEHYDE-3-PHOSPHATE DEHYDROGENASE AND 28S-RIBOSOMAL RNA GENE-EXPRESSION IN HUMAN HEPATOCELLULAR-CARCINOMA

The gene responsible for transcribing glyceraldehyde-3-phosphate dehyd rogenase (GAPDH) is commonly used as a reporter gene to estimate the a mount of RNA present in Northern analyses, However, recent data sugges t that GAPDH gene expression may vary with the extent of cell prolifer ation and differentiation. 28S-ribosomal RNA (28S-rRNA) has also been employed to normalize Northern blots prepared with total RNA. In the p resent study, we compared the expression of GAPDH messenger RNA (mRNA) with 28S-rRNA by Northern blot analyses in human hepatocellular carci noma tissues (HCC) and adjacent non-HCC tissues from eight patients wi th chronic viral hepatitis-induced cirrhosis and normal Liver tissue f rom eight healthy control subjects, The results of the study revealed that GAPDH mRNA levels in HCC were significantly higher (14x-16x) than those in adjacent non-HCC and normal liver tissues, Conversely, 28S-r RNA levels did not vary among HCC, adjacent nonHCC, and normal liver t issues, We also demonstrated that the 28S-RNA signal was proportional to the amount of RNA loaded, These findings indicate that 28S-rRNA rat her than GAPDH mRNA should be used as RNA loading controls for Norther n blot analyses involving HCC and nontumor tissues, The findings also raise the possibility that GAPDH mRNA gene expression might serve as a diagnostic indicator for human HCC.