Distinctive Expression Pattern of ZFX Variants in Breast Cancer Tissues

ZFX is a transcriptional regulator in embryonic stem cells that plays an important role in pluripotency and self-renewal property. ZFX is widely expressed in pluripotent stem cells and is down regulated during differentiation of embryonic stem cells. ZFX has five different variants that encode three different protein isoforms. While several reports have determined the overexpression of ZFX in a variety of somatic cancers, the expression of ZFX spliced variants in cancer cells is not well understood. In this study, the potential expression of ZFX variants was investigated in a series of breast cancer tissues and a series of stem and cancer cell lines, by using qPCR approach. Our results showed that the expression of ZFX-v1/3 and v4 are much higher in tumor tissues compared with marginal ones. In contrast, the ZFX-v5 is down regulated in tumor tissues. While the ZFX-v1/3 expression increased significantly in low-grade tumors, ZFX-v4 and v5 are highly expressed in high-grade ones. Here, our data revealed a significant association between HER2 status and the expression of ZFX spliced variants. Also, these variants are expressed in embryonic and adult stem cells, and so in most cancer cell lines; but they didn’t express in differentiated cell lines. Altogether, our findings suggest that the expression of ZFX spliced transcripts are various in different types of breast cancer types and may be contributed in tumorigenesis process of them. Hence, ZFX spliced transcripts can be considered as a novel tumor marker with potential diagnostic, prognostic and therapeutic value.