Interestingly, MCT1 is highly expressed at the leading tumor edge together with the Na+/H+ exchanger (NHE)1, whereas MCT4 is upregulated in the perinecrotic tumor center together with HIF-1α, LDH, and CAIX in GBM patients and in a rat glioma model [43,44,45]. The gene discussed is CA9; the disease is neoplasm.