Recent topics on α‐fetoprotein

Zinc‐fingers and homeoboxes 2 ( ZHX2 ) and zinc‐finger and BTB domain containing 20 ( ZBTB20 ) repress the postnatal expression of α‐fetoprotein ( AFP ) by interacting with the AFP gene promoter regions. ZHX2 inhibits the expression of AFP and cyclins A and E . ZBTB20 is negatively regulated by CUX1 , which promotes cell‐cycle progression, suggesting that AFP reactivation is closely linked to hepatocyte proliferation. A slight elevation in the serum AFP level often occurs in patients with chronic hepatitis C in the absence of hepatocellular carcinoma ( HCC ) and is an independent risk factor for HCC development to complement the fibrosis stage. In addition, the sustained elevation of AFP after interferon therapy is a risk factor of HCC development. AFP levels are clinically useful in predicting the outcomes of liver transplantation and sorafenib therapy for HCC patients. A low preoperative AFP level is a predictor of long‐term survival and is associated with a low recurrence rate of HCC after liver transplantation. AFP response (≥20% decrease in AFP during 6–8 weeks of treatment) rather than radiological outcomes is a significant prognostic factor for survival in sorafenib‐treated HCC patients. Highly sensitive Lens culinaris agglutinin‐reactive AFP ( AFP ‐ L3 ) is 5–10 times more sensitive than conventional AFP‐L3 , and useful for early detection of HCC in patients with total AFP below 20 ng/mL.