SLC9A1 and cancer: In line with this, the NHE1 activity was less affected in the cancer cells by the presence of external NaHCO3, especially in the CSCs (Figure 3B,C and Figure 4), which supports the data-mining analyses of acid–base transporter expression changes in PDAC showing that advanced PDAC has altered expression of NaHCO3 transporters and resulted in an increased expression of NHE1 [8,17,18].