CA9 and breast cancer: Experimental evidence for the role of CA IX in cell migration and invasion includes the CA IX suppression in HT1080 cells leading to reduced spreading and migration (Radvak et al., 2013), CA IX suppression in colorectal carcinoma cells leading to reduced invasion capacity in a COX-2 related manner (Sansone et al., 2009), as well as the pharmacologic inhibition of CA IX in mice xenografted with breast cancer cells leading to reduced growth of metastases (Gieling et al., 2012).