SLC9A1 and breast carcinoma: Increased dependency on Na+,HCO3– cotransport associates with severe breast cancer: enlarged CO2/HCO3–-dependent rises in pHi predict accelerated cell proliferation, whereas enhanced CO2/HCO3–-dependent net acid extrusion, elevated NBCn1 protein expression, and reduced NHE1 protein expression predict lymph node metastasis.