Methylation status of E-cadherin gene in gastric cardiac adenocarcinoma / 肿瘤

ABSTRACT

Objective: To investigate the methylation status of the promoter of E-cadherin gene and its protein expression in gastric cardiac adenocarcinoma(GCA). Methods: The methylation status of the 5′CpG island of E-cadherin was determined by a nested methylation specific PCR approach and E-cadherin protein expression was measured by immunohistochemical method in GCA tissues and adjacent tissues. Results: E-cadherin was methylated in 63 of 92 (68.5%) GCA specimens, which was significantly higher than that in paracancerous normal tissues (P < 0.001). Methylation occurred more frequently in patients at stage III and IV than those at stage I and II (P = 0.01). The frequency of methylation was significantly higher in poor differentiated group than moderate and well differentiated groups (P < 0.01). Immunohistochemical staining showed that E-cadherin expression was demonstrated heterogeneous, in 51 of 92 (44.6%) GCA specimens which was significantly different from matched paracancerous normal tissues. The positive rate of E-cadherin protein was significantly lower in patients at stage III and IV than those at stage I and II (P < 0.01). The positivity of E-cadherin was markedly lower in poor differentiated group compared with moderate and well differentiated groups, and the difference was significant (P < 0.05). Conclusion: Gene silencing caused by methylation of the 5′CpG island of E-cadherin gene may be one of the mechanisms for the tumorigenesis and development of GCA. The methylation status of E-cadherin could be used as a marker indicating the biological behaviors of GCA.