We selected formalin-fixed, paraffin-embedded samples of UC, cystitis, and normal canine bladders from the archive at the Veterinary Pathology Diagnostic Services at the University of Sydney (New South Wales, Australia). An anatomic pathologist confirmed the diagnoses of UC, cystitis, and normal before immunohistochemical analysis was performed. Carcinoma cases had also been confirmed by histopathology for tumor origin in the kidney, bladder, or urethra. Samples without propria-submucosa were excluded. Information collected from the medical records included age, sex, breed, date of treatment initiation, treatment protocol, outcome, and, when available, cause of death. Cause of death was classified as: related to primary UC (such as acute renal failure, urinary obstruction, uremia), related to metastatic UC, or associated with other diseases unrelated to UC. All cases were assessed histologically and graded according to the World Health Organization (WHO) tumor classification system 201610 (link)
; tumors are differentiated into 3 grades: G1, G2, and G3. The lowest grade (G1) displays slim papilla with no atypia; the highest grade (G3) displays major atypia with marked loss of normal architecture. A classification of G2 covers the wide spectrum of lesions seen between G1 and G3 and includes increasing layers within the papilla and rare atypia.
; tumors are differentiated into 3 grades: G1, G2, and G3. The lowest grade (G1) displays slim papilla with no atypia; the highest grade (G3) displays major atypia with marked loss of normal architecture. A classification of G2 covers the wide spectrum of lesions seen between G1 and G3 and includes increasing layers within the papilla and rare atypia.
