en Cancer Biology Cancer Biology مقاله کوتاه Short Communication Background: Previous studies have suggested that <em>BRCA1</em> dysregulation has been shown to have a role in triple-negative phenotypic manifestation. However, differences of <em>BRCA1</em> expression, as a tumor suppressor gene, have rarely been investigated between luminal and triple-negative breast tumors. Therefore, the present study&nbsp;attempted to compare the <em>BRCA1</em> expression in triple-negative with luminal breast tumors and its association with the clinicopathologic characteristics of patients. Methods:&nbsp;<em>BRCA1</em> expression was evaluated by real-time PCR in 26 triple-negative and 27 luminal breast tumors. Results:&nbsp;The results revealed that there is a high frequency of <em>BRCA1</em> underexpression in both triple-negative and luminal breast tumors. The <em>BRCA1</em> underexpression was related to young &nbsp;age at diagnosis, lymph node involvement, and grade ІІІ tumors. Conclusion:&nbsp;The observations suggest that decreased <em>BRCA1</em> expression, regardless of tumor subtype, has a general role in breast malignancy and associated with poor prognostic features in breast tumors. Breast cancer, BRCA1, Triple-negative breast neoplasm 210 214 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-1-671&slc_lang=en&sid=1 Farzaneh Darbeheshti No Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Pantea Izadi Yes Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Amir Nader Emami Razavi No Iran National Tumor Bank, Cancer Institute of Iran, Tehran University of Medical Sciences, Tehran, Iran Mir Saeed Yekaninejad No Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran and Javad Tavakkoly Bazzaz No Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences