Breast Cancer :: Health, Diseases

doorknocker Cancer as the most common cancer in Persian women affects women at least one decade younger than their counterparts in demonstrable countries. The highest frequency of malignancies has been observed in the 40-49 age groups 1.It is commonly accepted that estrogen and its receptor have an important role in the pathogenesis of meet malignancies. knocker tumors are classified based on ER status to ER negative and ER positive tumors. About 40% of tit tumors are ER negative 2. ER negative tumors in comparison to ER positive tumors tend to have worse prognosis and less belike to respond to endocrine therapy. This type of tumor is more prevalent in younger patients.Triple negative breast tumors (without ER and PR looking at and Her2 amplification) are the most clinically aggressive ones. Considering to the challenging nature of ER negative tumors treatment, and their innate poor prognosis, clarification of the molecular mechanisms that control formula of ER is essent ial. This knowledge may enable us to modify the spatial relation as such to restore sensitivity to endocrine therapies which provide us with opportunities for new therapeutic options for ER-breast tumors 3.Despite many studies on the mechanisms of electronegativity of ER in breast tumors, many details still rent to be clarified 4,5.The loss of ER expression in breast cancer may result from different underlying causes such as structural changes within the gene or transcriptional silencing 6. Abnormalities such as pass mutations, deletions, loss of heterozygosity or polymorphisms within the gene have not shown to be frequent enough to explain ER negativity phenotype6 7.In breast tumors such as other types of cancer, epigenetic alterations are common and are associate to gene expression modification8. It has been shown that tumor suppressor genes promoter methylation gives growth advantages to malignant cells9. Because of the potential reversible nature of epigenetic gene silencin g, epigenetic mechanisms have been under intemperate investigations in recent years 4, 6, 10, 11. Regarding to evidences which have been resulted from several in vitro (cell lines) and in vivo (animal models) studies, it has been shown that the inhibitors of DNA methyltransferase (DNMT) and histone deacetylase (HDAC) enzymes can reactivate ER expression in ER negative cells and restore response to endocrine therapy 12, 13. These promising landscape promote researchers to focus on the relationship between ER- phenotype and promoter methylation. However, heterogeneousness of the cellular population in breast tumors and differences in