CA9 and neoplasm: .Indeed, using the ethoxzolamide 72, a CAI in clinical use for decades as lead molecule, a multitude of primary sulphonamides (e.g. compounds 73–75) as well as the secondary siulfonamide 76 were reported to act as highly efficient, frequently low nanomolar inhibitors against the tumour-associated isoforms CA IX and XII.84–91