MTAP and urothelial carcinoma: To study the heterogeneity of MTAP expression loss and 9p21 deletions in advanced primary urothelial cancers of the urinary bladder, a tissue microarray (TMA) composed of five different tissue spots from different tissue blocks of 105 pT2-4 urothelial carcinomas was analyzed by immunohistochemistry (IHC) and fluorescence in-situ hybridization (FISH).