ERBB2 and neoplasm: Feline mammary carcinoma shares many epidemiological and histopathological characteristics with human breast cancer, in particular, the human epidermal receptor-2 (HER-2) positive and triple negative (TN) subtypes, having been proposed as a suitable model for their study4–6, and offers further opportunities for studying certain aspects of tumor biology, such as the crosstalk between the immune system and tumor development.