SCN5A and breast cancer: In breast cancer cells, the Na+ influx mediated through non-inactivated NaV1.5 channels was demonstrated to allosterically increase the activity of the Na+-H+ exchanger NHE1, thus promoting the efflux of H+ and further increasing the entry of Na+ into cancer cells, subsequently alkalinizing the intracellular pH and lowering the extracellular pH47,49,50.