Background: Hepatocellular carcinoma (HCC) is a common and rapidly fatal cancer. Current diagnostic methods for HCC have poor sensitivity and specificity, are invasive, and carry risk for complications. Newer markers are needed to overcome these problems and allow diagnosis of HCC at an earlier stage. In view of known associations between glycosylation changes and liver disease, we focused on the serum glycoprotein hemopexin and the specific characteristics of this liver-synthesized glycoprotein.
Methods: We studied 49 healthy volunteers and 81 patients divided into the categories of fibrosis, cirrhosis, and HCC with cirrhosis. Hemopexin was purified from study participants' serum by use of heme agarose beads. The hemopexin N-glycan profile was determined by use of the DNA sequencer-assisted fluorophore-assisted carbohydrate electrophoresis technique.
Results: We found that branching alpha-1,3-fucosylated multiantennary glycans on hemopexin were increased in the HCC group compared with the cirrhosis without HCC, fibrosis, and healthy volunteer groups, whereas nonmodified biantennary glycans decreased progressively across groups from fibrosis to the cirrhosis and HCC groups. Summarization of this information in a new marker, called the hemopexin glycan marker, enabled distinction of patients with HCC and cirrhosis from healthy volunteers and patients with fibrosis or cirrhosis with a sensitivity and specificity of 79% and 93%, respectively.
Conclusions: This study demonstrated hemopexin to be a model protein for studying liver-specific N-glycosylation. The hemopexin glycan marker could be a valuable complementary test to alpha-fetoprotein measurements for detection of HCC in patients with cirrhosis. Additional study of its utility for diagnosis and follow-up is recommended.