CDKN1A and urinary bladder carcinoma: We conclude that CDKN1A is a tumour suppressor gene in bladder carcinoma, and we note that its inactivation is a bladder-specific change, since >1% of cancers of other sites harbour CDKN1A mutations ( http://cancer.sanger.ac.uk/cosmic/gene/overview?ln=Cdkn1a).