Consensus proposal on essential phenothype markers and hormone receptor assessment in canine mammary tumors.

Introduction: Immunohistochemistry (IHC) has played an increasing role as a diagnostic tool for the identification of neoplasms and pathogens. In dogs with mammary tumors (CMTs), there have been an increasing number of studies looking for reliable diagnostic and/or prognostic immunohistochemical biomarkers but no consensus has been reached. These studies cannot be compared because of the differences in how these biomarkers have been used and evaluated. Materials and Methods: Review of the literature including IHC markers on CMTs in order to detect the best immunolabeling and evaluation systems for each marker. Results: After the review process, the authors reached a consensus regarding practical questions related to the methodology and provide guidelines on immunolabeling for CMTs markers along with the specific recommendations for interpretation of the results for each of these biomarkers in CMTs. Conclusion: By standardizing the methods used for labeling and interpretation of these IHC markers, we aim to ensure consistency and reproducibility of future study results.