Serum Alpha-Fetoprotein as a Biomarker in Liver Transplantation

Alpha-fetoprotein (AFP) is one of the most widely tested biomarkers in medicine. It has long been used in surveillance and diagnosis of hepatocellular carcinoma (HCC), the second cause of cancer-related death worldwide. Modern imaging modalities have replaced AFP in screening and diagnosis of HCC in the last decade. However, the establishment of liver transplantation as the gold standard treatment for HCC patients brought AFP back to the focus of interest. AFP was thoroughly investigated as a selection criterion for transplant candidates and a potential predictor of posttransplant HCC recurrence and survival. The general conclusion that can be made from all the studies is that high or rising AFP values indicate aggressive tumor biology and correlate with poor differentiation, micro-vascular invasion, posttransplant HCC recurrence, and reduced survival. Different AFP cutoff values were proposed, with or without being incorporated into transplant selection criteria or prognostic models. Because of the wide range of the proposed AFP cutoff values (from 15 to 1000 ng/nL) and the major diversity of the suggested selection criteria and prognostic models, there is no universal agreement on a specific role for AFP in liver transplantation till now. Prospective validation of AFP roles in large well-conducted randomized trials needs to be performed to come up with definite conclusions that can be applied to clinical practice. Also, multiple new biological and genetic markers are being studied in surveillance and diagnosis of HCC with promising results.