Objective：To explore the expression of brain-derived neurotrophic factor (BDNF) and its receptor (TrkB) protein in primary liver cancer and  the effects of exogenous BDNF on biological behavior  of liver cancer Bel-7402 cell line.
Methods：(1)The expression of BDNF and  TrkB was detected by immunohistochemistry in 8 cases of normal liver tissue, 48 cases of liver cancer(LC) and their respective surrounding tissue to analyze the relationships between BDNF, TrkB expression and the clinicopathological features, recurrence and survival rate in liver cancer; (2) cell proliferation, anoikis rate, adhesion, invasion and mobility ability as well as expression level of mRNA and protein of BDNF, TrkB, Bcl-2 in liver cancer cell line Bel-7402 and normal liver cell line L-02 were investigated.
Results：(1)Normal liver tissues showed negative expression for BDNF and  TrkB protein, however, in liver cancer, the positive rate of BDNF and TrkB protein was 69.0%(29/48) and 52.1%（25/48）, respectively, which was higher than those in their surrounding tissues（P＜0.05）. BDNF and  TrkB  positive rate had  significant  relations with Edmondson Grade, capsule formation and multiple nodules of tumor respectiverly（P＜0.05）. There was positive correlation of expressin BDNF and TrkB(r=0.332，P＜0.05). High expression of BDNF and TrkB in LC  significantly increased two year′s recurrence rate （P＜0.05） and decreased survival time(P＜0.01) ； (2)MTT and adhesion assay showed that BDNF can promote cell proliferation and ability of adhesion（P＜0.01）；(3) Flow cytometry showed that BDNF can enhance the ability to resist anoikis（P＜0.01）； (4) Transwell chamber assay and scrape migration assay showed that BDNF can enhance the ability of invasion and mobility of Bel-7402 in nonconcentration-dependent manner（P＜0.01）；(5)RT-PCR and Western Blot showed that BDNF can up-regulate the expression of mRNA and protein of Bcl-2 in Bel-7402 cells, respectively(P＜0.05).
Conclusions： (1) BDNF and TrkB protein are highly expressed  in liver cancer and may be related to recurrence and survival time; (2)  BDNF can modulate cell proliferation, adhesion, mobility and invasion in liver cancer Bel-7402 cell line; (3) BDNF can up-regulate the expression of Bcl-2 to inhibit the anoikis of Bel-7402 cell line.