Fig. 5
From: Carbonic anhydrase IX is a pH-stat that sets an acidic tumour extracellular pH in vivo

Comparison of in vivo pHi and pHe values for CA9 tumours. Median pHe values were derived from 1H MRS of ISUCA and pHe values from 31P MRS of endogenous metabolites in a separate cohort. The minimal overlap of the values supports the purely extracellular distribution for ISUCA previously demonstrated in vitro with C6 cells by Provent et al.20