Comparative oncology: overcoming human cancer through companion animal studies

Abstract

Comparative oncology is a field of study that has been recently adopted for studying cancer and developing cancer therapies. Companion animals such as dogs can be used to evaluate novel biomarkers or anticancer targets before clinical translation. Thus, the value of canine models is increasing, and numerous studies have been conducted to analyze similarities and differences between many types of spontaneously occurring cancers in canines and humans. A growing number of canine cancer models as well as research-grade reagents for these models are becoming available, leading to substantial growth in comparative oncology research spanning from basic science to clinical trials. In this review, we summarize comparative oncology studies that have been conducted on the molecular landscape of various canine cancers and highlight the importance of the integration of comparative biology into cancer research.

Canine on the Couch: The New Canary in the Coal Mine for Environmental Health Research

“…For many species and dogs in particular, comparative oncology research has heavily focused on shared genomics, pathobiological features, and therapeutics. A recent review article summarizes these shared genomic features 15 and will not be discussed here.…”

“…Among other molecular targets, overexpression of EGFR is seen in greater than 70% of urothelial carcinomas in both species. 15 A homologous mutation in exon 15 of the BRAF gene that is highly prevalent in canine urothelial carcinoma, although uncommon in most human bladder cancers, has recently been reported to have a higher incidence in humans with higher-risk tumors (i.e., larger masses and/or metastasis). 19 A cohort of humans with high-risk urothelial carcinoma, defined as a rate of 55% with a 2year metastasis, had BRAF mutations on 25% of cases.…”

“…It is estimated that six millions dogs per year are diagnosed with cancer in the United States . Many cancers that present as spontaneous disease in pet dogs share similar features with their human equivalents, including morphological appearance, molecular and genetic components, and biological and clinical behaviors. − Figure illustrates the corresponding cancers present in humans wherein the dog has been identified as an appropriate comparative model. ,,− …”

“…Cancers underlined have explored for shared environmental risk factors. Figure adapted and updated from Schiffman and Breen, 2015. ,,− …”

“…In addition to shared cytogenetic and genomic aberrations, canine urothelial carcinoma exhibits the same luminal and basal transcriptional subtypes as those seen in human urothelial carcinoma. Among other molecular targets, overexpression of EGFR is seen in greater than 70% of urothelial carcinomas in both species . A homologous mutation in exon 15 of the BRAF gene that is highly prevalent in canine urothelial carcinoma, although uncommon in most human bladder cancers, has recently been reported to have a higher incidence in humans with higher-risk tumors (i.e., larger masses and/or metastasis) .…”