CA9 and neoplasm: Interestingly, each drug alone decreased the percentage of cells that were Vimentin positive, but the combination of both inhibitors increased this percentage by ~14% (p < 0.001) (Figs 5B and S1C), providing further evidence that the combination of APE1/Ref-1 redox inhibition and CA9 inhibition results in preferential killing of tumor cells as opposed to CAF cells in this 3D co-culture system.