Vascular invasion is one of the clinicopathologic features that are associated with early recurrence of human hepatocellular carcinoma (HCC). In this study, we have employed high-density Affymetrix oligonucleotide GeneChips (Affymetrix, Santa Clara, CA) to compare the expression profiles of HCC with and without vascular invasion. Data mining of the gene expression database established revealed that leukocyte cell-derived chemotaxin-2 (LECT2) transcripts were downregulated in HCC patients with vascular invasion. Expression of LECT2 in human HCC biopsies was significantly reduced (Po0.0001, fold change ¼ À7.2) when compared with non-tumorous adjacent liver tissues. The reduction of LECT2 expression was significantly correlated with the early recurrent and poor prognosis of the patient (P ¼ 0.024). To validate the ability of LECT2 to repress the growth of HCC, an adenoviral vector encoding the secreted human LECT2 (AdLECT2) was introduced into the human HCC cell lines Hep3B and PLC/PRF/5, which do not express endogenous LECT2. Over-expression of LECT2 resulted in the significant inhibition of in vitro migration and invasion of the AdLECT2-transfected HCC cells. Additionally, over-expression of AdLECT2 in subcutaneous Hep3B tumor xenografts in athymic nude mice resulted in significant inhibition of tumor growth (Po0.05). In summary, our data not only demonstrated that LECT2 is a candidate prognostic marker of human HCC, but also that therapeutic strategies targeting LECT2 expression is a promising therapy for human HCC.