[Promoter methylation and expression of Runx3 gene in gastric cancer]

To analyze the relationships among the aberrant methylation of Runx3 gene promoter, the Runx3 protein expression and clinicopathological features in gastric cancer.

Methylation specific PCR was used to measure the promoter methylation status of Runx3 gene in tumor and the adjacent normal mucosal tissues from 40 patients with gastric cancer. Protein expression of Runx3 was measured by immunohistochemistry.

The frequency of promoter methylation of Runx3 gene in gastric cancer tissue(55.0%) was significantly higher compared to the adjacent normal tissues (12.5%)(P<0.01). The positive rate of protein expression of Runx3 in gastric cancer tissue(37.5%) was significantly lower compared to the adjacent normal tissues (100%). There was marked association between hypermethylation and negative protein expression (P<0.05). The frequency of Runx3 promoter methylation was associated with histological type, N grade, and tumor stage.

The promoter hypermethylation is a main mechanism of reduced or loss expression of Runx3 gene, which may provide molecular diagnosis and stage evaluation of gastric cancer.