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Identification of the genomic regions most intimately associated with non-Hodgkin lymphoma (NHL) pathogenesis is confounded by the genetic heterogeneity of human populations. We hypothesize that the restricted genetic variation of purebred dogs, combined with the contrasting architecture of the human and canine karyotypes, will increase the penetrance of fundamental NHL-associated chromosomal aberrations in both species. We surveyed non-random aneuploidy in 150 canine NHL cases, revealing limited genomic instability compared to their human counterparts and no evidence for CDKN2A/B deletion in canine B-cell NHL. ''Genomic recoding'' of canine NHL data into a ''virtual human'' chromosome format showed remarkably few regions of copy number aberration (CNA) shared between both species, restricted to regions of dog chromosomes 13 and 31, and human chromosomes 8 and 21. Our data suggest that gene discovery in NHL may be enhanced through comparative studies exploiting the less complex association between CNAs and tumor pathogenesis in canine patients. [ABSTRACT FROM AUTHOR]

Background: FMS-like tyrosine kinase 3 (FLT3) is a commonly mutated protein in a variety of human acute leukemias. Mutations leading to constitutively active FLT3, including internal tandem duplications of the juxtamembrane domain (ITD), result in continuous cellular proliferation, resistance to apoptotic cell death, and a poorer prognosis. A better understanding of the molecular consequences of FLT3 activation would allow improved therapeutic strategies in these patients. Canine lymphoproliferative diseases, including lymphoma and acute leukemias, share evolutionarily conserved chromosomal aberrations and exhibit conserved mutations within key oncogenes when compared to their human counterparts. A small percentage of canine acute lymphocytic leukemias (ALL) also exhibit FLT3 ITD mutations. Methods: We molecularly characterized FLT3 mutations in two dogs and one cell line, by DNA sequencing, gene expression analysis via quantitative real-time PCR, and sensitivity to the FLT3 inhibitor lestaurtinib via in vitro proliferation assays. FLT 3 and downstream mediators of FLT3 activation were assessed by Western blotting. Results: The canine B-cell leukemia cell line, GL-1, and neoplastic cells from 2/7 dogs diagnosed cytologically with ALL were found to have FLT3 ITD mutations and FLT3 mRNA up-regulation. Lestaurtinib, a small molecule FLT3 inhibitor, significantly inhibited the growth of GL-1 cells, while not affecting the growth of two other canine lymphoid cell lines without the FLT3 mutation. Finally, western blots were used to confirm the conserved downstream mediators of FLT3 activating mutations. Conclusions: These results show that ALL and FLT3 biology is conserved between canine and human patients, supporting the notion that canine ALL, in conjunction with the GL-1 cell line, will be useful in the development of a relevant large animal model to aid in the study of human FLT3 mutant leukemias. [ABSTRACT FROM AUTHOR]

The generation of a 7.5x dog genome assembly provides exciting new opportunities to interpret tumor-associated chromosome aberrations at the biological level. We present a genomic microarray for array comparative genomic hybridization (aCGH) analysis in the dog, comprising 275 bacterial artificial chromosome (BAC) clones spaced at intervals of approximately 10 Mb. Each clone has been positioned accurately within the genome assembly and assigned to a unique chromosome location by fluorescence in situ hybridization (FISH) analysis, both individually and as chromosome-specific BAC pools. The microarray also contains clones representing the dog orthologues of 31 genes implicated in human cancers. FISH analysis of the 10-Mb BAC clone set indicated excellent coverage of each dog chromosome by the genome assembly. The order of clones was consistent with the assembly, but the cytogenetic intervals between clones were variable. We demonstrate the application of the BAC array for aCGH analysis to identify both whole and partial chromosome imbalances using a canine histiocytic sarcoma case. Using BAC clones selected from the array as probes, multicolor FISH analysis was used to further characterize these imbalances, revealing numerous structural chromosome rearrangements. We outline the value of a combined aCGH/FISH approach, together with a well-annotated dog genome assembly, in canine and comparative cancer studies. [ABSTRACT FROM AUTHOR]

The generation of a 7.5× dog genome assembly provides exciting new opportunities to interpret tumor-associated chromosome aberrations at the biological level. We present a genomic microarray for array comparative genomic hybridization (aCGH) analysis in the dog, comprising 275 bacterial artificial chromosome (BAC) clones spaced at intervals of approximately 10 Mb. Each clone has been positioned accurately within the genome assembly and assigned to a unique chromosome location by fluorescence in situ hybridization (FISH) analysis, both individually and as chromosome-specific BAC pools. The microarray also contains clones representing the dog orthologues of 31 genes implicated in human cancers. FISH analysis of the 10-Mb BAC clone set indicated excellent coverage of each dog chromosome by the genome assembly. The order of clones was consistent with the assembly, but the cytogenetic intervals between clones were variable. We demonstrate the application of the BAC array for aCGH analysis to identify both whole and partial chromosome imbalances using a canine histiocytic sarcoma case. Using BAC clones selected from the array as probes, multicolor FISH analysis was used to further characterize these imbalances, revealing numerous structural chromosome rearrangements. We outline the value of a combined aCGH/FISH approach, together with a well-annotated dog genome assembly, in canine and comparative cancer studies. [ABSTRACT FROM PUBLISHER]

Background: FMS-like tyrosine kinase 3 (FLT3) is a commonly mutated protein in a variety of human acute leukemias. Mutations leading to constitutively active FLT3, including internal tandem duplications of the juxtamembrane domain (ITD), result in continuous cellular proliferation, resistance to apoptotic cell death, and a poorer prognosis. A better understanding of the molecular consequences of FLT3 activation would allow improved therapeutic strategies in these patients. Canine lymphoproliferative diseases, including lymphoma and acute leukemias, share evolutionarily conserved chromosomal aberrations and exhibit conserved mutations within key oncogenes when compared to their human counterparts. A small percentage of canine acute lymphocytic leukemias (ALL) also exhibit FLT3 ITD mutations.Methods: We molecularly characterized FLT3 mutations in two dogs and one cell line, by DNA sequencing, gene expression analysis via quantitative real-time PCR, and sensitivity to the FLT3 inhibitor lestaurtinib via in vitro proliferation assays. FLT 3 and downstream mediators of FLT3 activation were assessed by Western blotting.Results: The canine B-cell leukemia cell line, GL-1, and neoplastic cells from 2/7 dogs diagnosed cytologically with ALL were found to have FLT3 ITD mutations and FLT3 mRNA up-regulation. Lestaurtinib, a small molecule FLT3 inhibitor, significantly inhibited the growth of GL-1 cells, while not affecting the growth of two other canine lymphoid cell lines without the FLT3 mutation. Finally, western blots were used to confirm the conserved downstream mediators of FLT3 activating mutations.Conclusions: These results show that ALL and FLT3 biology is conserved between canine and human patients, supporting the notion that canine ALL, in conjunction with the GL-1 cell line, will be useful in the development of a relevant large animal model to aid in the study of human FLT3 mutant leukemias. [ABSTRACT FROM AUTHOR]