en Medical Genetics Medical Genetics Original Research Original Research <p> <strong> Abstract </strong></p><p> <strong> Background: </strong>The Iranian breast cancer patients are relatively younger than their </p><p>  Western counterparts. Evidence suggests that alterations in estrogen signaling pathways , including estrogen receptor-α (ER- α ), occur during breast cancer development in Caucasians. Epidemiologic studies have revealed that age-incidence patterns of breast cancer in Asians differ from those in Caucasians. Genomic data for </p><p>  ER- α in either population is therefore of value in the clinical setting for the Iranian </p><p>  breast cancer . </p><p> <strong> Methods: </strong>A case-control study was conducted to establish a database of ERpolymorphisms in Iranian women population in order to compare Western and Asian </p><p>  with Iranian (Asian-Caucasians) distributions and to evaluate ER- polymorphism as </p><p>  an indicator of clinical outcome. DNA samples were prepared from Iranian women </p><p>  with breast cancer referred to Imam Khomeini Hospital Complex clinical breast cancer </p><p>  group (150 patients) and in healthy individuals (147 healthy control individuals ). PCR single-strand conformation polymorphism technology was performed . </p><p> <strong> Results: </strong>Asite of silent single nucleotide polymorphism (SNP) was found, as reported </p><p>  previously in Western and Eastern studies, but at significantly different frequencies . </p><p>  The frequency of allele 1 in codon 325 (CCC}CCG) was significantly </p><p>  higher in the breast cancer patients (39.6%) than control individuals (28.9% P = </p><p>  0.007). The allele 1 had also significant association with the occurrence of lymph </p><p>  node metastasis . </p><p> <strong> Conclusion: </strong>Data suggested that ER- α polymorphisms in exon 4 codon 325 was </p><p>  correlated with various aspects of breast cancer in Iran. ER- α genotype, as determined </p><p>  during presurgical evaluation, might represent a surrogate marker for predicting </p><p>  the breast cancer lymph node metastasis . </p><p>  </p> breast cancer, estrogen receptor- α, polymorphism, PCR-SSCP, Lymph node metastasis 75 82 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-64&slc_lang=en&sid=1 Cyrus Azimi 20031947532846001802 20031947532846001802 No Department of Genetics, Cancer Institute, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran. Sakineh Abbasi abbasisk@tums.ac.ir 20031947532846001803 20031947532846001803 Yes Department of Medical Laboratory Sciences, Faculty of AlliedMedicine, Tehran University of Medical Sciences, Tehran, Iran