Assessment of Tumor-Associated Tissue Eosinophilia (TATE) and Tumor-Associated Macrophages (TAMs) in Canine Transitional Cell Carcinoma of the Urinary Bladder

Simple Summary Transitional cell carcinoma of the urinary bladder in dogs is a severe type of cancer with difficult treatment and recovery. These dog cancers are quite similar to bladder cancers in humans, making them a good comparison for study. This research looked into how certain types of immune cells, specifically eosinophils (referred to as tumor-associated tissue eosinophils) and macrophages (tumor-associated macrophages), affect the development and severity of these cancers. This study examined 34 cases of dog bladder cancer and used specific staining techniques to identify eosinophils and macrophages. The tumors were divided into two groups based on their aggressiveness (low- and high-grade). It was found that the less severe cancers had more eosinophils, while the more severe ones had more macrophages. This suggests that the presence of these immune cells is linked to how aggressive the cancer is. This study proposes that targeting these cells could be a new way to treat this type of cancer in dogs, which might also provide insights into human cancer treatment.Abstract Transitional cell carcinoma of the urinary bladder is a significant neoplasm in dogs, characterized by a poor prognosis and a high metastatic potential. These canine spontaneous tumors share many characteristics with human transitional cell carcinoma, making them an excellent comparative model. The role of inflammatory infiltration in tumor development and progression is frequently contradictory, especially concerning tumor-associated tissue eosinophils (TATE) and tumor-associated macrophages (TAMs). This study aims to analyze TATE and TAMs in canine transitional cell carcinoma of the urinary bladder. Congo Red staining was used to identify TATE, and immunohistochemistry was performed to detect TAMs in 34 cases of canine transitional cell carcinoma of the bladder carcinomas, categorized into low and high grades. Statistically significant differences were observed between the number of eosinophils and macrophages in the two groups of tumors. The number of TATE was higher in low-grade malignant tumors, but the number of TAMs was higher in high-grade tumors. Our findings suggest the importance of TATEs and TAMs in the aggressiveness of canine transitional cell carcinoma and propose their potential use as therapeutic targets.