Previously, relative mRNA expressions of TGF-β receptors and R-Smads were compared in various triple negative breast cancer cell lines, but the data failed to correlate TGF-β resistance to altered Smad or TGF-β receptor mRNA expression levels [40, 41] because of breast cancer heterogeneity that included all types of breast cancers. This evidence concerns the gene TGFB1 and breast cancer.