"Lassie," "Toto," and fellow pet dogs: poised to lead the way for advances in cancer prevention.

Abstract

Cancer causes substantial morbidity and takes the lives of over 8 million people worldwide each year. Advances in cancer prevention research are crucial, and animal models are key to this. There are many valuable experimentally induced cancer models, but these do not fully meet the needs for cancer prevention studies. Pet dogs with risks for naturally occurring cancer can fill important gaps in cancer prevention research. Using invasive urothelial carcinoma (iUC) as an example, the advantages of utilizing pet dogs include: (1) close similarities between dogs and humans in carcinogenesis, molecular and cellular features, invasive and metastatic behavior, and response to treatment, thus providing high relevance for comparative studies, (2) shared environment between dogs and humans to help identify not-yet-known environmental iUC risks, (3) strong breed-associated risk (5- to 21-fold increased risk compared with mixed breeds) that facilitates investigation of gene-environment interactions, screening, and early intervention, (4) large size of dogs (versus rodents) that allows collection of fluids and tissues via cystoscopy, and detailed imaging at multiple time points, and (5) acceptance for studies in which each participating dog can benefit while enjoying life in their family environment, and in which findings will help other dogs and humans. An ongoing 3-year study in Scottish Terriers (comparable to a 15- to 20-year study in humans) is aimed at defining genetic and environmental risk factors for iUC, effective methods for screening/early detection, and a successful secondary cancer prevention approach with very promising results to date. Pet dogs can indeed propel cancer prevention research.