AIMS: To assess the production of a liver-specific protein, albumin, and of a master transcriptional factor, hepatocyte nuclear factor (HNF)-4alpha, in hepatoid adenocarcinoma tissue. METHODS: Standard and quantitative RT-PCR, using five cases of hepatoid and three cases of non-hepatoid gastric adenocarcinoma. RESULTS: Hepatoid adenocarcinomas expressed similarly large amounts of albumin mRNA as those expressed in hepatocellular carcinoma and normal liver tissues. The observed amounts were several hundred times more than those in non-hepatoid adenocarcinoma and normal stomach tissues. HNF-4alpha mRNA was expressed in all stomach samples examined, and the levels of expression did not quantitatively differ between hepatoid and non-hepatoid adenocarcinomas of the stomach. CONCLUSIONS: These results provide further support of a relationship between hepatic transdifferentiation in hepatoid adenocarcinomas and albumin mRNA expression. Furthermore, transdifferentiation to the hepatocytic phenotype in hepatoid adenocarcinoma tissue was not directly associated with HNF-4alpha expression, thus suggesting that transdifferentiation proceeds by a complicated mechanism.
AIMS: To assess the production of a liver-specific protein, albumin, and of a master transcriptional factor, hepatocyte nuclear factor (HNF)-4alpha, in hepatoid adenocarcinoma tissue. METHODS: Standard and quantitative RT-PCR, using five cases of hepatoid and three cases of non-hepatoid gastric adenocarcinoma. RESULTS:Hepatoid adenocarcinomas expressed similarly large amounts of albumin mRNA as those expressed in hepatocellular carcinoma and normal liver tissues. The observed amounts were several hundred times more than those in non-hepatoid adenocarcinoma and normal stomach tissues. HNF-4alpha mRNA was expressed in all stomach samples examined, and the levels of expression did not quantitatively differ between hepatoid and non-hepatoid adenocarcinomas of the stomach. CONCLUSIONS: These results provide further support of a relationship between hepatic transdifferentiation in hepatoid adenocarcinomas and albumin mRNA expression. Furthermore, transdifferentiation to the hepatocytic phenotype in hepatoid adenocarcinoma tissue was not directly associated with HNF-4alpha expression, thus suggesting that transdifferentiation proceeds by a complicated mechanism.