Table 2 briefly summarizes some major pH regulators in tumours and their main functions, including anion exchangers (SLC4A1, SLC4A2, and SLC4A3), proton transporter vacuolar ATPase (V-ATPase), mono-carboxylate transporters (MCT1, MCT2, MCT3, and MCT4), sodium ion based chloride/bicarbonate exchanger (SLC4A8) and Na+/H+ exchanger 1 (SLC9A1).50–59. This evidence concerns the gene SLC9A1 and neoplasm.