Whereas loss or attenuation of TGF-β signaling is permissive for transformation, blocking receptor function in metastatic breast cancer (BC) cells has been shown to inhibit survival, EMT, invasiveness, and metastatic dissemination, suggesting that TGF-β promotes tumor development and malignancy through autocrine and/or paracrine mechanisms [11]. This evidence concerns the gene TGFB1 and breast cancer.