Background/aims: Ornithine decarboxylase is essential for cell growth. Its activity was high in human hepatocellular carcinoma tissues and was highest in poorly differentiated tumors.
Methodology: To find if there are tumor-specific ornithine decarboxylases, we examined the ornithine decarboxylase cDNA sequences of 91 clones prepared from hepatoma tissue and non-cancerous tissue of resected liver specimens from 15 patients with hepatocellular carcinoma.
Results: Ornithine decarboxylase gene mutations were more frequently detected in the hepatoma tissue. The incidence of mutation in hepatoma tissue was related to dedifferentiation. Mutation in regions rich in proline, glutamic acid, serine, and threonine were detected in moderately and poorly differentiated hepatocellular carcinoma only.
Conclusions: Our findings suggested that the sequence of ornithine decarboxylase in hepatocellular carcinoma often is different from that in normal liver and that mutation of its gene is related to the progression of hepatocellular carcinoma.