High expression of 23 kDa protein of augmenter of liver regeneration (ALR) in human hepatocellular carcinoma

Background: Augmenter of liver regeneration (ALR) is an important polypeptide that participates in the process of liver regeneration. Two forms of ALR proteins are expressed in hepatocytes. Previous data have shown that ALR is essential for cell survival and has potential antimetastatic properties in hepatocellular carcinoma (HCC). Aims: The study aimed to evaluate the expression levels of two forms of ALR proteins in HCC and their possible significance in HCC development. Methods: Balb/c mouse monoclonal antibody against ALR protein was prepared in order to detect the ALR protein in HCC by Western blotting and immunohistochemistry. ALR mRNA expression levels were measured by real-time polymerase chain reaction in HCC tissues and compared to paracancerous liver tissues in 22 HCC patients. Results: ALR mRNA expression in HCC liver tissues (1.51x10(6) copies/mu L) was higher than in paracancerous tissues (1.04x10(4) copies/mu L). ALR protein expression was also enhanced in HCC liver tissues. The enhanced ALR protein was shown to be 23 kDa by Western blotting. Immunohistochemical analysis showed that the 23 kDa ALR protein mainly existed in the hepatocyte cytosol. Conclusion: The 23 kDa ALR protein was highly expressed in HCC and may play an important role in hepatocarcinogenesis.