AFP and hepatocellular carcinoma: Previously, we had found that extracellular AFP was able to stimulate the growth of HCC cells or other cancer cells, which was mediated by AFPR 8, 28; cytoplasmic AFP blocked retinoic acid receptor β interaction with the promoter of fibroblast growth factor‐inducible 14 (Fn14) gene to promote the expression of Fn14, and led to HCC cells antagonist all trans retinoic acid to induce apoptosis 29; these results exhibited that the intracellular or extracellular AFP contributed to malignant behaviours of HCC cells.