en باکتری شناسی پزشکی Medical bacteriology پژوهشي Research <div style="text-align: justify;"><strong>Background:</strong> Cancer is amongst the leading reasons of death in all parts of the world. Breast cancer is also responsible for the largest number of deaths among women population. Several studies confirmed that<em> Bifidobacterium bifidum</em> as a probiotic meaningfully inhibited breast cancer development. The present study aimed to investigate the effect of <em>B. bifidum</em> supernatant on the cell growth inhibition of the breast cancer 4T1 cell line, in vitro.<br> <strong>Materials and methods:</strong> The present experimental work was conducted at Mazandaran University of Medical Sciences (MAZUMS), Sari, Iran. <em>B. bifidum</em> was cultured in the MRS broth at 37&deg;C for 72 hours anaerobically and the <em>B. bifidum</em> supernatant (BS) was prepared by the freezing-thawing procedure. The cell growth inhibition of the probiotic strain was assessed using the MTT assay through breast cancer (4T1) cell line.<br> <strong>Results:</strong> The results showed that the supernatant extracted from <em>B.bifidum</em> strain had good antiproliferative effects against 4T1 cancer cell line, compared to control group. The inhibitory effects growing with increased time.<br> <strong>Conclusion:</strong> <em>B. bifidum</em> supernatant could be considered as a as potential probiotic candidates in the treatment of breast cancer. However, further in vitro/in vivo studies are required to complement our initial findings.</div> Breast cancer, Bifidobacterium bifidum, 4T1 cell line, MTT 1 6 http://rmm.mazums.ac.ir/browse.php?a_code=A-10-1062-1&slc_lang=en&sid=1 Parisima Karami parikarami72@gmail.com 10031947532846008509 10031947532846008509 Yes Department of Microbiology and virology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Saeid Abediankenari abedianks@razi.tums.ac.ir 10031947532846008510 10031947532846008510 No Department of Immunology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Hamid Reza Goli goli59@gmail.com 10031947532846008511 10031947532846008511 No Molecular and Cell Biology Research Centre, Faculty of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Mehrdad Gholami mehrdad_gholami90@YAHOO.COM 10031947532846008512 10031947532846008512 No Department of Microbiology and virology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran Mohammad Ahanjan ahanjan2007@gmail.com 10031947532846008513 10031947532846008513 No Department of Microbiology and virology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran