CAFs freshly isolated from tumor-bearing KPfC-mice also expressed a highly active NHE1, with the resting pHi and the rate of NHE1-dependent recovery being similar to PSCs cultured at pHe7.4 (vehicle-treated KPfC-mice: pH recovery: 0.44 ± 0.09 pH unit/min, n cells/N mice = 11/3). Here, SLC9A1 is linked to neoplasm.