Abstract:

Objective

To analyze the status of Runx3 gene promoter methylation and explore its association with the expression of Runx3 gene and clinicopathological factors of breast cancer.

Methods

From February 2007 to April 2009,a total of 56 breast cancer tissue samples and corresponding pericancer tissues were collected and used for this study.All samples were confirmed pathologically.Methylation-specific PCR (polymerase chain reaction)was performed to detect the promoter hypermethylation of Runx3 gene,and analyze its influence on the expression of Runx3 gene and the relationship between Runx3 promoter methylation and clinicopathological factors in breast cancer.Chi-square test and Pearson test were used for statistical analysis.

Results

The rate of promoter hypermethylation of Runx3 gene in the breast cancer tissues(55.4%)was significantly higher than that in the pericancer tissues(10.7%),with statistical difference between the two(χ²=25.225,P=0.000).Runx3 gene hypermethylation was related with clinical staging and lymph node metastasis(P=0.018,P=0.010),but not related with the age,tumour size and histological types(P＞0.050).There was a light association between the expression of Runx3 m RNA and Runx3 promoter methylation (r=0.343,P=0.010).

Conclusions

Runx3 promoter methylation can lead to a decrease or absence in the runx3 mRNA expression in breast cancer.The promoter methylation of Runx3 gene can induce the inhibition of Runx3 m RNA expression,which might be one of the mechanisms of Runx3 gene inactivation in human breast cancer.

Key words: Breast neoplasms, Runx3 gene, Promoter regions,Methylation, Methylation-specific PCR