Diagnostic value of the hemopexin N-glycan profile in hepatocellular carcinoma patients.

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.

Increased fucosylation and reduced branching of serum glycoprotein N-glycans in all known subtypes of congenital disorder of glycosylation I.

The N-glycans present on the total mixture of serum glycoproteins (serum N-glycome) were analyzed in 24 subjects with congenital disorder of glycosylation type I (CDG-I) and 7 healthy, age-matched individuals. No new N-glycan structures were observed in the sera of CDG-I patients as compared with normal sera. However, we observed in all subtypes a significantly increased degree of core alpha-1,6-fucosylation of the biantennary glycans as compared to normal, as well as a significant decrease in the amount of triantennary glycans. These serum N-glycome changes appear to be a milder manifestation of some of the changes observed in adult liver cirrhosis patients, which is compatible with the reported steatosis and fibrosis in CDG-I patients. In the CDG-Ia subgroup, the extent of the serum N-glycome changes correlates with the aberration of the serum transferrin isoelectric focusing pattern, which measures the severity of the lack of entire N-glycan chains (primary consequence of CDG-I) in the liver and is the standard diagnostic test for this category of inherited diseases.