Mozhgan Rasti - Department of Biochemistry, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
Rita Arabsolghar - Department of Biochemistry, Medical School, Shiraz University of Medical Sciences, Shiraz, Iran
Sajad Azmand - Pharmaceutical Science Research Center, Shiraz University of Medical Sciences, Shiraz, Iran

Background:Many breast cancer tumor suppressor genes have been reported to undergo hypermethylation, including ER, RASSF۱A, HIC, CDH۱, GSPT۱, APC, TWIST and CCND۲. We first determined the promoter methylation of the above eight tumor suppressor genes as epigenetic markers of breast cancer in three cell lines with different ER status.Methods: This study was an experimental study performed on three cell lines: ER-positive MCF-۷, ER-negative MDA-MB-۴۶۸ and the ER- and HER۲-positive breast cancer cell line (BT-۴۷۴). For this purpose DNA was extracted from these cell lines and gene promoter methylation was analyzed by methylation-specific PCR.Results: Our results showed that all studied genes were hypermethylated in ER- negative MDA-MB-۴۶۸ cells. We detected hypermethylation of GSPT۱, RASSF۱A and CCND۲ genes in these three cell lines. In addition, the ER-positive MCF-۷ cells showed methylation of TWIST and APC genes.Conclusion: The numbers of methylated molecular biomarkers is increased with tumor progression.This finding may be important in breast cancer therapy for different ER status.