The identification of TBX3 as a potential regulator of early breast cancer progression from DCIS to IMC is of potential clinical utility not only in identifying which DCIS lesions may be more likely to progress to invasion, but along with a better understanding of the role of specific TBX3-induced gene expression changes, in providing other potential molecular targets to block breast cancer progression at this early, pre-invasive stage. The gene discussed is TBX3; the disease is ductal breast carcinoma in situ.