SLC9A1 and cancer: Indeed, upregulation of NHE1 is observed in tumour cells (McLean et al., 2000; Ober and Pardee, 1987) and overexpression of NHE1 in fibroblasts induces the glycolytic phenotype and drives malignant transformation (Reshkin et al., 2000), suggesting that pH changes in tumour cells are a primary factor in the progression of cancer.