title: Promoter hypermethylation of estrogen receptor alpha gene is correlated to estrogen receptor negativity in Iranian patients with sporadic breast cancer.
abstract: OBJECTIVE
  Breast Cancer is the most common cancer in Iranian women. Breast tumors are classified based on the estrogen receptor alpha (ERα) expression status into ER negative and ER positive tumors. ER negative tumors tend to have worse prognosis and less likely to respond to endocrine therapy. Aberrant methylation of gene promoter is one of the mechanisms for gene silencing in breast tumors. Because of its reversible nature, promoter methylation is a good target for new therapeutic strategies. We aimed to evaluate the frequency of this epigenetic event in ERα gene and its association to clinicopathological features in Iranian breast cancer patients.
  
  
  METHODS
  In this case control study the patient series consisted of 100 sporadic primary breast cancer cases (51 ER negative and 49 ER positive tumors). None of the participants had chemo or radiotherapy before surgery. In breast tumors ERα promoter methylation were assessed with methylation specific polymerase chain reaction (MSP). Data was collected on clinicopathological features of the patients. Correlation between ERα methylation and clinicopathological characteristics of the patients was investigated by Pearson Chi-Square and Fisher's exact test.
  
  
  RESULTS
  ERα methylation was detected in 98% of ER negative and 65% of ER positive breast tumors. A strong correlation was found between ERα methylation and ER negativity in tumors (p<0.0001). Also, ERα methylation has associated to progesterone receptor negativity (p<0.008) and double receptor negative status (p<0.0001) in breast tumors.
  
  
  CONCLUSIONS
  ERα methylation occurs with high frequency in the breast tumors of Iranian breast cancer patients and may play a considerable role in pathogenesis of ERα negative tumors as a poor prognosis and more aggressive category. The reversible nature of DNA methylation may provide new therapeutic possibilities in ER negative breast tumors.
authors.affiliation: 1. Department of Medical Genetics, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran.
authors.forename: Pantea
authors.initials: P
authors.lastname: Izadi
authors.forename: Mehrdad
authors.initials: M
authors.lastname: Noruzinia
authors.forename: Morteza
authors.initials: M
authors.lastname: Karimipoor
authors.forename: Mohammad Hamid
authors.initials: MH
authors.lastname: Karbassian
authors.forename: Mohammad Taghi
authors.initials: MT
authors.lastname: Akbari
keywords: Breast Cancer; Estrogen Receptor; Methylation