ERBB2 and breast carcinoma: On the other hand, TBX3, which encodes for the T-box transcription factor 3, is significantly more expressed in HER2-positive (n = 4120) than in HER2-negative (n = 683) breast cancers (Fig. 6D) and lower TBX3 expression is predictive of poor DMFS and DFS in HER2-positive breast cancer patients (Fig. 6F, high versus low TBX3 p = 0.0004 and p = 0.0075).