SLC9A1 and cancer: The Na+/H+ exchanger isoform 1 (NHE1) proton transporter is known to be specifically involved in cellular acid-base balance in cancer cells, where it contributes to cytosolic pH homeostasis, cell transformation, proliferation, tumor growth, invasion, activation of the metastatic process, and resistance to chemotherapy (Cardone et al., 2005; Stock et al., 2008; Reshkin et al., 2013).