Quantitative analysis of promoter methylation of the EDNRB gene in gastric cancer

Hypermethylation has been shown in the promoter region of the endothelin receptor B (EDNRB) gene in several human tumors. However, its role in gastric cancer formation is still unclear. In this study, the methylation status of the EDNRB gene in paired gastric cancer tissues and adjacent normal tissues from 96 patients was detected quantitatively using pyrosequencing. The results showed the methylation of promoter of EDNRB gene in gastric cancer (50.42 ± 9.03%) was significantly higher than in adjacent normal tissues (6.47 ± 2.98%) (P < 0.01). Among 96 tumor tissues, promoter hypermethylation of the EDNRB gene was correlated with tumor infiltration (T1: 47.4 ± 7.31% T2:48.2 ± 9.17% T3:52.9 ± 6.48% T4:53.2 ± 10.45%), lymph node metastasis (N0:45.4 ± 6.99% N1:49.0 ± 9.10% N2:52.0 ± 8.40% N3:53.7 ± 9.92%), and distant metastasis (M0:48.9 ± 6.99% M1:53.9 ± 11.98%) (P < 0.05), but it was not associated with other clinicopathological characteristics. In addition, the treatment of the human gastric cancer cell line, SGC-7901, with demethylation agent can restore the expression of EDNRB. Our results suggest that promoter hypermethylation of EDNRB gene is highly prevalent in gastric cancer, which may play a role in the pathogenesis of gastric cancer. Futhermore, hypermethylation of EDNRB gene was remarkably related to infiltration and metastasis of gastric cancer and may attribute to the tumor progression.