A search for diagnostic and prognostic markers in canine mammary tumours: Possibilities and pitfalls

Canine mammary tumours (CMTs) are the most common neoplasms in female dogs, presenting significant challenges in veterinary oncology due to their diverse biological behaviour and potential for metastasis. CMTs are recorded in most countries of the world and almost all States in India. The risk factors responsible for the CMTs are breed, age, sex, steroid hormones and reproductive status. Grossly, the CMTs appear as small or large masses, soft to hard, fixed or freely movable with sizes ranging from small nodules to large, pedunculated or sessile growths. The cytological features of CMTs are distinct for benign tumours, malignant tumours and atypical category. Histologically, the CMTs are classified into different subtypes of benign and malignant tumours. The malignant epithelial tumours further classified into various subtypes of carcinomas. The special type of malignant tumour includes various types of epithelial and mesenchymal tumours. Immunohistochemically, the CMTs reveal varied expression for epithelial, mesenchymal and proliferative markers, metastatic markers, cancer stem cells, angiogenesis, hormone receptors and triple negative phenotypes.