A potential role for the homeoprotein Hhex in hepatocellular carcinoma progression

Hepatocellular carcinoma (HCC), the most common primary malignant tumor of the liver, often associated with the dysregulation of transcriptional pathways involved in cell growth and differentiation. The hematopoietically expressed homeobox protein (Hhex) is an important transcription factor throughout liver development and is essential to liver bud formation and hepatoblast differentiation. Here, we report a relationship between Hhex expression and HCC. First, adenovirus-mediated Hhex delivery into the hepatoma cell line, Hepa1-6, resulted in decreased expression of several proto-oncogenes (c-Jun and Bcl2), increased expression of some tumor suppressor genes (P53 and Rb), and enhanced expression of a cluster of hepatocytic and bile ductular markers. Second, Hhex expression significantly attenuated Hepa1-6 tumorigenicity in nude mice. Third, we report a correlation between Hhex expression and the differentiation state of human HCC. In 24 cases of clinical specimens, there was a significant difference in Hhex expression between poorly differentiated HCC and well-differentiated HCC (P < 0.001). Taken together, these results indicate that Hhex is a potential candidate molecular marker for HCC pathological evaluation, suggesting a need to evaluate Hhex as a potential target for therapeutic intervention.