Breast cancer remains a lethal disease to women due to lymph node metastasis, the tumor microenvironment, secondary resistance and other unknown factors. Several important transcription factors involved in this disease, such as PTEN, p53 and beta-catenin, have been identified and researched in-depth as candidates for targeted therapy in breast cancer. TFDP3 is a new, promising candidate for transcriptional regulation in breast cancer, although it was first identified in hepatocellular carcinoma. Here, we demonstrate that TFDP3 is expressed in a variety of malignancies, normal testis tissue and breast cancer cell lines and thus provide evidence that TFDP3 is a cancer-testis antigen. We illustrate that overexpression or silencing TFDP3 interferes with epithelial-mesenchymal transition but does not influence cell proliferation, indicating that the TFDP3 protein acts as a transcription factor during epithelial-mesenchymal transition. These data highlight that TFDP3 is expressed in breast cancer, that it is a member of the cancer-testis antigen family and that it functions as a regulator in epithelial-mesenchymal transition.