en Molecular Genetics & Genomics Molecular Genetics & Genomics مقاله کامل Full Length/Original Article <strong>Background</strong>: Young age at first full-term pregnancy (FFTP) is an important factor in breast cancer risk reduction. It is postulated that this protective effect is the result of stable molecular signatures imprinted by physiological process of pregnancy, but the molecular mechanism of this protective role is unclear. The aim of the current study was to identify the effect of early FFTP on methylation status of <em>FOXA1</em> gene body. FOXA1 is an essential transcription factor for mammary gland development and estrogen responsiveness of breast tissue. <strong>Methods</strong>: Fresh frozen normal breast tissues (n = 51) were collected from Iranian women who underwent cosmetic mammoplasty (27 nulliparous women and 24 parous women who have experienced first pregnancy before the age of 25). DNA was extracted and then methylated DNA immunoprecipitation (MeDIP) real-time PCR was used to assess <em>FOXA1</em> gene body methylation. <strong>Results:</strong> Our results revealed that <em>FOXA1</em> methylation level is significantly higher in early parous compared with nulliparous group (<em>p </em>= 0.041). <strong>Conclusion:</strong> Our study provides new hint about the association between early FFTP and epigenetic modifications within gene body of <em>FOXA1</em> in normal breast tissue. More investigation is required for clarifying molecular mechanisms underlying this association in order to develop breast cancer prevention strategies.&nbsp; Breast cancer, DNA methylation, Epigenetics, FOXA1, Pregnancy 99 106 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-1-742&slc_lang=en&sid=1 Zahra Zendehbad 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 Abdolreza Daraei 0000-0002-2106-835X No Genetic Department, Faculty of Medicine, Babol University of Medical Sciences, Babol, Iran Mir Saeed Yekaninejad 0000-0003-3648-5276 No Department of Epidemiology and Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran Nahid Nafissi 0000-0001-7454-9985 No Surgical Department, School of Medicine, Iran University of Medical Science, Tehran, Iran Nasim Younosi No Surgical Department, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran Ghasemali Khorasani No Division of Plastic and Reconstructive Surgery, Imam Khomeini Hospital Complex, Tehran University of Medical Sciences, Tehran, Iran Javad Tavakkoly Bazzaz 0000-0003-1623-1463 No Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran