Nucleolar organizer regions in transitional cell tumors of the bladder

The traditional silver staining technique that identifies nucleolar organizer region-associated proteins has recently been adapted and applied to paraffin sections, and used to examine changes in nucleolar organizer region numbers in a variety of benign and malignant conditions. We describe herein the enumeration of nucleolar organizer regions in a variety of benign and malignant conditions of the transitional epithelium of the urinary bladder. While there is a statistical separation between normal and neoplastic groups, there is a degree of overlap between normal, inflammatory, dysplastic, and neoplastic urothelium.