Furthermore, the ureidosulfonamide and glycosyl coumarin inhibitors were effective in reducing lung metastases (Lou et al., 2011; Pacchiano et al., 2011), as was a sulfamate inhibitor of CAIX (Gieling et al., 2012), and in depleting CSCs in models of breast cancer metastasis (Lock et al., 2013), showing the value of CAIX inhibitors as therapeutic agents for use in targeting metastasis and chemoresistant tumor initiating cells. Here, CA9 is linked to breast cancer.