BACKGROUND: Epigenetic regulation such as aberrant hypermethylation of CpG 
islands in promoter plays a key role in tumorigenesis. 5-Aza-2'-deoxycytidine 
(5-aza-CdR) which is a potent inhibitor of DNA methylation can reverse the 
abnormal hypermethylation of the silenced tumor suppressor genes (TSGs). It has 
been reported that hepatocyte cell adhesion molecule (hepaCAM) acts as a tumor 
suppressor gene and expression of its mRNA and protein were down-regulated in 
bladder cancer. Over-expression of hepaCAM can inhibit cancer growth and arrest 
renal cancer cells at G0/G1 phase. In this study, we investigated the 
methylation status of hepaCAM gene, as well as the influence of 5-aza-CdR on 
expression of hepaCAM gene in bladder cancer cells.
METHODS: CpG islands in hepaCAM promoter and methprimers were predicted and 
designed using bioinformatics program. Methylation status of hepaCAM promoter 
was evaluated in bladder cancer tissues and two cell lines (T24 and BIU-87) by 
Methylation-specific PCR; Western blot and Immunofluorescence were used to 
detect expression of hepaCAM protein after 5-aza-CdR treatment; Flow cytometry 
assay was performed to determine effectiveness of 5-aza-CdR on cell cycle 
profile.
RESULTS: CpG island in promoter of hepaCAM gene was hyper-methylated both in 
bladder carcinoma tissues and cell lines (T24 and BIU-87). Otherwise, aberrant 
methylation of its promoter was associated with its decreased expression. 
Hypermethylation of hepaCAM gene was reversed and expression of its mRNA and 
protein were re-activated in two cell lines by DNA methyltransferases inhibitor 
5-aza-CdR. Flow cytometry assay demonstrated that 5-aza-CdR can inhibit growth 
of cancer cells by arresting cancer cells at G0/G1 phase.
CONCLUSION: Abnormal hypermethylation in CpG island of hepaCAM promoter is 
involved in absence of hepaCAM gene expression when bladder cancer occurs. 
Re-activation of hepaCAM gene by 5-aza-CdR can inhibit growth of cancer cells 
and arrest cells at G0/G1 phase.