For instance, it was demonstrated that the TGF-β signaling pathway acts as a tumor suppressor at early stage of mammary carcinogenesis(Elliott and Blobe, 2005), while at later stages, as tumor progresses, levels of TGF-β increase and then it acts as a breast cancer stimulator (Walker and Dearing, 1992). This evidence concerns the gene TGFB1 and neoplasm.