en Cancer Biology Cancer Biology مقاله کامل Full Length/Original Article <strong>Background:</strong> ZFX is a transcriptional regulator in embryonic stem cells and plays an important role in pluripotency and self-renewal. <em>ZFX</em> is widely expressed in pluripotent stem cells and is down-regulated during differentiation of embryonic stem cells. <em>ZFX</em> has five different variants that encode three different protein isoforms. While several reports have determined the overexpression of <em>ZFX</em> in a variety of somatic cancers, the expression of <em>ZFX</em>-spliced variants in cancer cells is not well-understood. <strong>Methods:</strong> We investigated the expression of <em>ZFX</em> variants in a series of breast cancer tissues and cell lines using quantitative PCR. <strong>Results:</strong> The expression of <em>ZFX </em>variant 1/3 was higher in tumor tissue compared to marginal tissue. In contrast, the <em>ZFX </em>variant 5 was down-regulated in tumor tissues. While the <em>ZFX </em>variant 1/3 and <em>ZFX</em> variant 5 expression significantly increased in low-grade tumors, <em>ZFX </em>variant 4 was strongly expressed in high-grade tumors, demonstrating lymphatic invasion. In addition, our result revealed a significant association between the HER2 status and the expression of <em>ZFX</em>-spliced variants.&nbsp;<strong>Conclusion:</strong> Our data suggest that the expression of <em>ZFX</em>-spliced transcripts varies between different types of breast cancer and may contribute to their tumorigenesis process. Hence, <em>ZFX</em>-spliced transcripts could be considered as novel tumor markers with a probable value in diagnosis, prognosis, and therapy of breast cancer. Breast neoplasms, Neoplastic stem cells, RNA splicing 47 56 http://ibj.pasteur.ac.ir/browse.php?a_code=A-10-1-729&slc_lang=en&sid=1 Fatemeh Pourkeramati No Department of Biotechnology, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran Malek Hossein Asadi Yes Department of Biotechnology, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran Shahryar Shakeri No Department of Biotechnology, Institute of Science and High Technology and Environmental Sciences, Graduate University of Advanced Technology, Kerman, Iran Alireza Farsinejad No Pathology and Stem Cell Research Center, Kerman University of Medical Sciences, Kerman, Iran