part of part of basal cell urothelial cell basal cell of urothelium A basal cell that is part of the urothelium. Compared to other urothelial cell types, a basal cell of the urothelium is positioned along the basement membrane, is the most undifferentiated and serves a progenitor role. It has been noted in at least some mammalian species that the urothelial basal cell type is distinguished by expression of high levels of cytokeratin-5 (CK5), p63 and the signalling molecule Sonic hedgehog (Shh). Similar to intermediate cells, the urothelial basal cell type expresses CK17 but is negative for uroplakins (UPK) and CK20. Urothelial basal cells have also been noted to be smaller in diameter than urothelial intermediate cells. urothelial basal cell FMA:84150 urothelium