Comparing human breast cancer with canine mammary cancer

Abstract

Tumors arising spontaneously in human and canine mammary gland tissue appear to have many common clinical features. This book chapter gives an overview of the incidence, risk factors, histological appearance, tumor genetics, biological behavior, molecular targets, and treatment responses in human breast cancer patients and dogs with mammary carcinomas. In both species, malignant tumors of the mammary gland are the most frequent neoplasms in females. Accordingly, the sexual steroid hormones, estrogen and progesterone, are considered not only to play a major role in the development of normal but also of neoplastic mammary gland tissue in both species. While most of the tumorigenic mutations arise during the life span of the affected individual, hereditary mutations like BRCA1 and BRCA2, p53, and PTEN are detectable in dogs and humans. Many diagnostic procedures, classification systems, and numerous prognostic features are similar in human and canine patients, though veterinarians tend not to have the same standardized procedures mostly due to the owners’ financial limitations. Nonetheless, spontaneous mammary tumors in dogs provide important proof-of-concept models to support preclinical transgenic or xenograft rodent models in the development of new treatment strategies for human and consequently also canine patients.