Considering the fact that the treatment with TGF-β1 increased SCN5A expression, and that TGF-β1-induced increase in MCF7 cancer cell invasiveness was prevented by the use TTX, it is most likely that NaV1.5 channels expressed and functional (giving rise to sodium currents) at the plasma membrane of cancer cells are responsible for this effect. The gene discussed is SCN5A; the disease is cancer.