In breast cancer, a SIRT1-PRRX1-KLF4-ALDH1 circuitry has been identified, in which SIRT1 deacetylases and stabilizes the epithelial-to-mesenchymal-transition inducer, PRRX1, by inhibiting its proteasomal degradation [210]. The gene discussed is SIRT1; the disease is breast carcinoma.