AFP-L3: a new generation of tumor marker for hepatocellular carcinoma

Background: Alpha-fetoprotein (AFP) from hepatocellular carcinoma (HCC) dis plays differential affinity to lectin Lens culinaris agglutinin (LCA) compa red to that from chronic hepatitis/liver cirrhosis. According to their bind ing capability to LCA, total AFP can be separated into three different glyc oforms, AFP-L1, AFP-L2, and AFP-L3. AFP-L1 is the non-LCA-bound fraction, w hich constitutes the major glycoform of AFP in serum of chronic hepatitis a nd liver cirrhosis. AFP-L3 is the LCA-bound fraction of AFP. It has been re ported that malignant liver cells produce AFP-L3, even when HCC is at its e arly stages, and especially when the tumor mass is supplied by the hepatic artery. Clinical research has determined that AFP-L3 is a highly specific m arker for HCC. The AFP-L3 can be detected in the serum of approximately 35% of the patients with small HCC ( < 2 cm). The AFP-L3-positive HCC has pote ntial for rapid growth and early metastasis. Compared to imaging techniques , it has been shown to have 9-12 months of lead-time in early HCC recogniti on. Combined sensitivity of AFP-L3 for HCC is 56%, with a specificity of > 95%. Methods: Automated assay for measuring AFP-L3 has been developed and i ntroduced in clinical use. The new automated method for measurement of ALP- L3 is based on liquid phase binding of the AFP-L3 glycoform with LCA and tw o specific monoclonal antibodies labeled with peroxidase and polysulfated t yrosine peptide, respectively. Conclusion: AFP-L3 is a new generation of tu mor marker for HCC and yields useful information on HCC for clinical decisi on making. (C) 2001 Elsevier Science B.V. All rights reserved.