Moreover, knockdown of NHE1 or NBCn1 (SLC4A7) in the MDA-MB-231 cell line significantly reduced the steady-state intracellular pH value after acid load, the ability to restore pHi and the primary tumor growth of xenografts in vivo, but NBCn1 knockdown prolonged tumor-free survival and reduced cell proliferation [114, 115]. The gene discussed is SLC9A1; the disease is neoplasm.