Objective To investigate the expression of kallikrein 9 (KLK9) in liver cancer and to determine its significance.Methods The expression of KLK9 in liver cancer was detected by immunohistochemistry and RT-PCR techniques.Results The rate of expression of KLK9 protein in liver cancer tissues was significantly higher than paracarcinoma tissues and normal liver tissues (P ＜ 0.05).The expression of KLK9 mRNA in liver cancer cells was significantly higher than normal liver cells (P ＜ 0.05).The expression of KLK9 was related to metastasis,size of tumors,degree of malignancy and clinical staging of the liver cancer (P ≤ 0.05),but there was no associated with age,HbsAg and sex (P ＞ 0.05).Conclusions KLK9 may play an important role in the occurrence and development of liver cancer.It may be used as a tumor marker and a prognostic factor.It may also provide a theoretical basis for the diagnosis and biological targeted therapy of liver cancer.

Objective To probe the gene expression of normal epithelial cell specific-1 (NES1) in normal liver cells and liver cancer cell lines , and investigate the gene methylation status and its impacts on gene expression and cell biology .Methods The expression level of NES1 mRNA was detected in HepG2 and L02 cells by RT-PCR and RT-QPCR, and the level of gene methylation was examined by MSP .We de-tected cell viability by MTT , NES1 mRNA by RT-QPCR and cyclinD1, P21 and P53 level by Western blot after treating cells with 5-Aza-CdR.Results Compared with L02, NES1 mRNA expression in HepG2 was significantly reduced, and the level of NES1 exon 3 CpG island methylation in HepG2 cells was much higher than that in L02 cells.After demethylation , NES1 mRNA expression and protein level of p 21 and p53 in HepG2 cells were up-regulated , while the cell viability and the level of CyclinD 1 were decreased .Conclu-sions In hepatocellular carcinoma , low expression of NES1 mRNA is related to the gene exon 3 CpG island methylation .NES1 exon 3 methylation may be one of the molecular mechanisms for reducing NES 1 mRNA level, and 5-aza-dC could inhibit cell proliferation by inducing cell cycle arrest in HepG 2 cells.