Density of tumor-infiltrating granzyme B-positive cells predicts favorable prognosis in dogs with transitional cell carcinoma.

Abstract

Although tumor-infiltrating lymphocytes (TILs) play a key role in anti-tumor immunity, their involvement in canine transitional cell carcinoma (TCC) is not well-documented. The objective of this study was to investigate the association between TIL number and prognosis in dogs with urinary bladder TCC. Immunohistochemical analysis of CD3 and granzyme B was performed using canine TCC (n=32) and normal bladder (n=10) tissues. The numbers of CD3and granzyme Bcells located in peritumoral stroma of canine TCC were significantly higher than those in normal controls. In TCC cases, the number of CD3TILs was not significantly related to prognosis, whereas the abundant granzyme BTILs were associated with favorable outcome. Since granzyme BTILs were not associated with the tumor stage, the presence of granzyme BTILs may be an independent prognostic factor. These results suggest that granzyme BTILs play a role in anti-tumor immunity and inhibit tumor progression in canine TCC.