This appears consistent with the preclinical work by Schepkin et al. [30] who observed elevated sodium MR signal without alterations in proton ADC during tumor recurrence and studies that have observed an increase in intracellular sodium with increasing tumor cell proliferation due to abnormal Na+/K+-ATPase and NHE activity in glioma cells [17–19]. The gene discussed is SLC9C1; the disease is glioma.