Some of the Luminal A-specific TF regulators include SMAD4, which was shown to induce apoptosis in ERα-positive breast cancer cells (Li et al. 2005); NKX2-1 (also known as TTF-1), which regulates genes in the thyroid, lungs, and diencephalon during embryogenesis and whose expression has been detected in a small proportion of breast carcinomas (Robens et al. 2010); and FOXA1, which has been studied within the ERα pathway in luminal breast cancers and found to correlate with patient survival (Badve et al. 2007). Here, SMAD4 is linked to breast carcinoma.