BCSG1 methylation status and BCSG1 expression in breast tissues derived from Chinese women with breast cancer.

OBJECTIVE: To investigate the role of DNA methylation in the regulation of BCSG1 gene expression in breast tissues derived from Chinese women with breast cancer. METHODS: The methylation status of exon 1 of the BCSG1 gene in breast cancer, and matched non-neoplastic adjacent and benign lesion tissues was extensively examined using methylation-specific PCR analysis. Corresponding mRNA expression levels were determined by real-time PCR. RESULTS: We found: (1) the BCSG1 gene was universally demethylated in all breast tissues regardless of the tissue state, although 50-60% of the samples displayed methylated products as well; (2) DNA methylation correlated to the expression of the BCSG1 gene in tumor tissues, but not in non-neoplastic adjacent and benign tissues; (3) breast tumor tissues expressed lower BCSG1 than non-neoplastic adjacent tissues. CONCLUSIONS: Our data revealed a unique expression pattern and methylation status of the BCSG1 gene in breast tissues derived from Chinese patients and suggested both methylation status and mechanisms underlying BCSG1 regulation might be closely related to the racial background.