Investigation of neutrophil extracellular traps in canine mammary tumors

This study aimed to investigate the relationship between tumor grade and tumor infiltrating neutrophils and neutrophil extracellular traps (NETs) in canine breast cancers. For this purpose, 20 canine breast cancer blocks were used. Following the histopathological classification of the cases, the tumors were graded according to mitotic figure, tubule formation, and degree of differentiation. Citrullinated histone-3 (cith3) and myeloperoxidase (MPO) antibodies were used for staining to reveal NETs in the tumor tissue. Staining was performed using the fading and re-staining method on the same sections. The stained sections were then colored with the program, overlaid, and false immunofluorescence images were obtained. In the tumor tissue, NETs were scored based on the presence of cith3 positive areas and compared with tumor grade. The diagnoses of the cases used in the study were malignant mixed tumor, cystic papillary carcinoma, complex carcinoma, solid carcinoma, tubulopapillary carcinoma, comedo carcinoma, micropapillary carcinoma, lipid-rich carcinoma, squamous cell carcinoma, adenosquamous carcinoma, carcinoma with malignant myoepithelioma, and fibrosarcoma. When the cases were divided into three groups according to tumor grade and comparisons were made between groups, it was seen that the neutrophil score numerically increased as the tumor grade increased. The NET score was observed to have a slight numerical superiority in the group with tumor grade 1 compared to other groups. It was noteworthy that the necrosis score was also numerically higher in grade II and III tumors than grade I tumors. According to the analysis results, a low-degree negative correlation was observed between tumor grade and NET score (r = -0.361). No significance was observed between tumor grade and neutrophil and necrosis score. According to the study results, it was observed that NETs were found at varying degrees in breast tumors and there was a low-grade negative correlation between NET levels and tumor grade. However, no relationship was found between NETs, neutrophil levels, and necrosis observed in the tumor tissue Keywords: Dog, double immunohistochemistry, extracellular trap, mammary tumor, neutrophil