The selective importance of Na+,HCO3– cotransport and NBCn1 expression was supported by our finding that NHE1 protein expression was reduced in primary breast cancer tissue from patients with lymph node metastases (Figure 8E) and qualified as an independent predictor negatively related to metastatic risk with an odds ratio of 0.60 (Figure 8G). The gene discussed is SLC9A1; the disease is metastatic malignant neoplasm in the lymph nodes.