The simultaneous deletion of Lkb1 and Pten in the mouse bladder resulted in diffusely hyperplasic atypical urothelium with papillary growths and the tumours were histologically similar to human neoplasms: by day 100 resembled a low grade papillary urothelial carcinoma and turned into high grade by day 125 [61]. The gene discussed is PTEN; the disease is neoplasm.