While knockdown of MCT1 or NBCn1 was rather efficient (75–80 %) and inhibited growth, and the effect was similar to that of the corresponding pharmacological agents, NHE1 knockdown was less efficient (50 %), and the lack of effect of NHE1 inhibition or knockdown was puzzling, given the previously reported roles of this transporter in cancer cell proliferation and growth [10, 14]. The gene discussed is SLC9A1; the disease is cancer.