TBX3 and cancer: Due to the growing literature implicating TBX3 in the promotion of tumorigenesis in several cancer types [3–7, 9, 10, 12, 18, 19], and the observation of tissue- and species-specific TBX3 isoform ratios [3], it is essential to address the functional relevance of TBX3 isoforms and their altered expression in cancer.