To date, several studies have shown that in solid tumors NHE1, as the most important cellular pH regulator, is upregulated, which can be regarded as an adaptive response of cancer cells to hypoxia and acidosis, and that the resulting intracellular alkalinization and extracellular acidification play crucial roles in cancer cell proliferation, invasion and metastasis [122, 123]. The gene discussed is SLC9A1; the disease is cancer.