SIRT1 has been demonstrated to modulate several intracellular signaling protein molecules, including protein kinase B (PKB), B-cell lymphoma 2 (Bcl-2), metadherin (MTDH), Frizzled 7, EMT-related proteins, and the cluster of differentiation 36 (CD36), in breast cancer cells. This evidence concerns the gene MTDH and breast cancer.