title: Homologous Mutation to Human BRAF V600E Is Common in Naturally Occurring Canine Bladder Cancer--Evidence for a Relevant Model System and Urine-Based Diagnostic Test.
abstract: Targeted cancer therapies offer great clinical promise, but treatment resistance is common, and basic research aimed at overcoming this challenge is limited by reduced genomic and biologic complexity in artificially induced rodent tumors compared with their human counterparts. Animal models that more faithfully recapitulate genotype-specific human pathology could improve the predictive value of these investigations. Here, a newly identified animal model for oncogenic BRAF-driven cancers is described. With 20,000 new cases in the United States each year, canine invasive transitional cell carcinoma of the bladder (InvTCC) is a common, naturally occurring malignancy that shares significant histologic, biologic, and clinical phenotypes with human muscle invasive bladder cancer. In order to identify somatic drivers of canine InvTCC, the complete transcriptome for multiple tumors was determined by RNAseq. All tumors harbored a somatic mutation that is homologous to the human BRAF(V600E) mutation, and an identical mutation was present in 87% of 62 additional canine InvTCC tumors. The mutation was also detectable in the urine sediments of all dogs tested with mutation-positive tumors. Functional experiments suggest that, like human tumors, canine activating BRAF mutations potently stimulate the MAPK pathway. Cell lines with the mutation have elevated levels of phosphorylated MEK, compared with a line with wild-type BRAF. This effect can be diminished through application of the BRAF(V600E) inhibitor vemurafenib. These findings set the stage for canine InvTCC as a powerful system to evaluate BRAF-targeted therapies, as well as therapies designed to overcome resistance, which could enhance treatment of both human and canine cancers
  
  
  CONCLUSIONS
  This study demonstrates the activating BRAF mutation (V600E), which is found in multiple human cancers, is a driver of canine InvTCC, and highlights a urine-based test for quick diagnosis.
authors.affiliation: Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland. University of Cambridge, Cambridge, United Kingdom.
authors.forename: Brennan
authors.initials: B
authors.lastname: Decker
authors.affiliation: Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Heidi G
authors.initials: HG
authors.lastname: Parker
authors.affiliation: Purdue Comparative Oncology Program, Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, Indiana.
authors.forename: Deepika
authors.initials: D
authors.lastname: Dhawan
authors.affiliation: Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Erika M
authors.initials: EM
authors.lastname: Kwon
authors.affiliation: Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Eric
authors.initials: E
authors.lastname: Karlins
authors.affiliation: Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland.
authors.forename: Brian W
authors.initials: BW
authors.lastname: Davis
authors.affiliation: Department of Comparative Pathobiology, Purdue University, West Lafayette, Indiana.
authors.forename: José A
authors.initials: JA
authors.lastname: Ramos-Vara
authors.affiliation: Purdue Comparative Oncology Program, Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, Indiana.
authors.forename: Patty L
authors.initials: PL
authors.lastname: Bonney
authors.affiliation: Cummings School of Veterinary Medicine, Tufts University, North Grafton, Massachusetts.
authors.forename: Elizabeth A
authors.initials: EA
authors.lastname: McNiel
authors.affiliation: Purdue Comparative Oncology Program, Department of Veterinary Clinical Sciences, Purdue University, West Lafayette, Indiana. Purdue University Center for Cancer Research, West Lafayette, Indiana.
authors.forename: Deborah W
authors.initials: DW
authors.lastname: Knapp
authors.affiliation: Cancer Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland. eostrand@mail.nih.gov.
authors.forename: Elaine A
authors.initials: EA
authors.lastname: Ostrander
mesh_terms: D000818:Animals; D003955:Diagnostic Tests, Routine / Q000379:methods; D004285:Dogs; D006801:Humans; D009154:Mutation; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics* / Q000652:urine; D012689:Sequence Homology, Nucleic Acid; D001749:Urinary Bladder Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000652:urine
chemical_list: C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf