Comparative oncology today

Abstract

The value of comparative oncology has been increasingly recognized in the field of cancer research, including the identification of cancer-associated genes; the study of environmental risk factors, tumor biology, and progression; and, perhaps most importantly, the evaluation of novel cancer therapeutics. The fruits of this effort are expected to be the creation of better and more specific drugs to benefit veterinary and human patients who have cancer. The state of the comparative oncology field is outlined in this article, with an emphasis on cancer in dogs.

Figure 1. Advantages of Comparative Oncology

Cancer is a prevalent disease in dogs. The pet owning public is highly motivated to seek advanced care for their pets and are interested in both traditional and experimental therapies. Comparative Oncology aims to utilize the dog as a sophisticated model for the study cancer biology and therapy. Attributes of this opportunity are numerous. Cancer in dogs naturally share many of the genetic aberrations, oncogene over expression and tumor suppressor loss seen in the human disease. This provides a platform for the evaluation of target biology. Importantly pet dogs with cancer capture the complexity of cancer by representing tumor heterogeneity both within individual tumors and between patients with the same diagnosis, in a way impossible in traditional research models. Thus allowing for the study of metastasis biology, disease recurrence and resistance patterns in true clinical patients, corresponding to the key elements of the problem of cancer in man.

Figure 2. Comparative Oncology Focused Clinical Trial Design

Comparative Oncology clinical trial designs focus on answering specific questions important for optimal drug development. The opportunity for serial biopsy of tumor, normal tissues, and other biofluids before, during and after exposure to new agents is readily incorporated into study designs. Biological evaluation of these tissues/samples can now include gene expression analysis, SNP and CGH array genomics, and all protein based analyses common in human studies. These evaluations can occur in parallel with advanced imaging studies including CT, MR, PET and PET/CT. Thus these studies allow for the unique correlation of drug exposure to tissue and fluid biomarkers and dynamic imaging endpoints. The anticipation is that studies in pet dogs will improve the efficiency of toxicological assessment and also have the potential to evaluate biology and activity in a natural occurring tumor model.