Genomic analyses identify 15 susceptibility loci and reveal HDAC2, SOX2-OT, and IGF2BP2 in a naturally-occurring canine model of gastric cancer.

Gastric cancer (GC) is the fifth most common human cancer worldwide, but the genetic etiology is largely unknown. We performed a Bayesian genome-wide association study and selection analyses in a naturally-occurring canine model of GC, the Belgian Tervuren and Sheepdog breeds, to elucidate underlying genetic risk factors. We identified 15 loci with over 90% predictive accuracy for the GC phenotype. Variant filtering revealed germline putative regulatory variants for the EPAS1 (HIF2A) and PTEN genes and a coding variant in CD101. Although closely related to Tervuren and Sheepdogs, Belgian Malinois rarely develop GC. Across-breed analyses uncovered protective haplotypes under selection in Malinois at SOX2-OT and IGF2BP2. Among Tervuren and Sheepdogs, HDAC2 putative regulatory variants were present at comparatively high frequency and were associated with GC. Here, we describe a complex genetic architecture governing GC in a dog model, including genes such as PDZRN3, that have not been associated with human GC.

Randomised trial evaluating chemotherapy alone or chemotherapy and a novel monoclonal antibody for canine T-cell lymphoma: A multicentre US study.

Background: Canine peripheral nodal T-cell lymphoma is considered chemotherapy resistant and carries a relatively poor prognosis. Prospective evaluations reporting the impact of chemotherapy on progression-free survival (PFS) and overall survival time for dogs with T-cell lymphoma are lacking. This study examined the impact of L-CHOP (L-asparaginase, doxorubicin, cyclophosphamide, vincristine, prednisone) chemotherapy or L-CHOP in combination with AT-005, a US Department of Agriculture-licensed caninised monoclonal antibody, on PFS and response rates in dogs with clinical intermediate- and high-grade peripheral nodal T-cell lymphoma. Methods: A prospective, randomised, placebo-controlled, investigator- and owner-blinded, multicentre study was completed. All dogs received a 19-week L-CHOP chemotherapy protocol with randomisation (1:1) into placebo or AT-005 groups. Response was evaluated via the Veterinary Cooperative Oncology Group criteria for canine lymphoma. Results: Forty-nine dogs were enrolled (25 received placebo and 24 received AT-005). Most demographic factors were similar between the two groups, with the exception that more dogs with stage IV and V disease were treated with AT-005 (34% vs. 8%; p = 0.03). Median PFS was 103 days (95% confidence interval [CI], 56-118) in the placebo group versus 64 days (95% CI, 36-118) in the AT-005 group. The overall response rate (ORR) for all dogs was 98% (48 of 49); complete response rate in the placebo group (64%) was not different from the AT-005 group (67%). Conclusions: To the best of the authors' knowledge, this is the first prospective study to document that treatment with L-CHOP chemotherapy, with or without AT-005, may result in a high ORR, but relatively brief PFS in dogs with clinical intermediate- and high-grade T-cell lymphoma.

Use of a canine melanoma vaccine in the management of malignant melanoma in an African penguin (Spheniscus demersus).

CASE DESCRIPTION: A 25-year-old 4.4-kg male aquarium-hatched African penguin (Spheniscus demersus) was evaluated because of a raised 1.5 × 0.5-cm pigmented mass extending from within the right naris noted 2 days earlier. CLINICAL FINDINGS: The penguin had a raised pigmented mass extending out from the right naris and onto the upper beak. Histologic examination of excisional biopsy specimens confirmed a diagnosis of malignant melanoma. A treatment plan including administration of meloxicam, radiation therapy, and immunotherapy was initiated. TREATMENT AND OUTCOME: Treatment with meloxicam (0.2 mg/kg, PO, q 24 h) was initiated and continued for a total of 45 weeks; however, the medication was discontinued for a period of 6 weeks because of the risk of toxic effects in the chick that the penguin was feeding at that time. The penguin underwent local hypofractionated radiation therapy and received 4 once weekly 8-Gy fractions of radiation (total radiation dose, 32 Gy). The penguin was administered a canine melanoma vaccine transdermally every other week for 4 doses, with a booster injection given 7 months after the first dose. Treatment with the vaccine appeared to have no adverse effects. The penguin's pre- and postvaccination tyrosinase-specific antibody titers were measured with an anti-human tyrosinase-specific ELISA, and a 3-fold titer increase indicated a positive humoral immune response to the canine melanoma vaccination. The penguin died of unrelated causes 54 weeks after initial diagnosis, and there was no evidence of metastasis on necropsy. CLINICAL RELEVANCE: These case findings suggested that vaccination with a canine melanoma vaccine may be a safe and useful adjunct treatment for management of malignant melanoma in penguins.

Risk and characteristics of gastric carcinoma in the chow chow dog.

Gastric carcinoma is not commonly reported in dogs. There is an increased risk, however, in certain breeds such as the Belgian Tervuren. Review of the Veterinary Medical Database (VMDB) established an increase in risk for gastric carcinoma in the chow chow breed. In 106 chow chow dogs signs commenced, on average, 3 weeks before definitive diagnosis. The most common clinical signs were vomiting, loss of appetite, diarrhea, and melena. Most affected dogs were euthanized, without treatment, within 2 weeks of diagnosis. Two dogs which were treated aggressively (surgery and chemotherapy) survived a considerably longer time (12 and 36 months). Histologically, these chow chow dogs comprised a similar histologic type as familial gastric carcinoma in humans; diffuse-type carcinoma that was enriched in the signet ring and mucinous variants. Understanding the pathogenesis of diffuse gastric carcinoma in the chow chow dog may provide insight into the biology of this aggressive cancer in humans.

Risques et caractéristiques d'un carcinome gastrique chez le chien de race chow-chow. Le carcinome gastrique n'est par rapporté fréquemment chez les chiens. Il y a toutefois une augmentation du risque chez certaines espèces telle que le Tervuren belge. Une revue de la base de données Veterinary Medical Database (VMDB) a établi une augmentation dans le risque pour le carcinome gastrique chez la race chow chow. Chez 106 chiens chow chow les signes débutèrent, en moyenne, 3 semaines avant le diagnostic définitif. Les signes cliniques les plus fréquents étaient vomissement, perte d'appétit, diarrhée et méléna. La plupart des chiens affectés furent euthanasiés, sans traitement, à l'intérieur de 2 semaines du diagnostic. Deux chiens furent traités de manière agressive (chirurgie et chimiothérapie) ont survécu beaucoup plus longtemps (12 et 36 mois). Histologiquement, ces chiens chow chow comprennent un type histologique similaire aux carcinomes gastrique familiaux chez les humains; le carcinome de type-diffus qui s'est développé dans les variants de cellules en bague à chatons et mucineux. Comprendre la pathogénie du carcinome gastrique diffus chez le chien chow chow pourrait fournir des informations sur la biologie de ce cancer agressif chez l'humain.(Traduit par Dr Serge Messier).

Correction: Comparative oncology DNA sequencing of canine T cell lymphoma via human hotspot panel.

[This corrects the article DOI: 10.18632/oncotarget.25209.].

Comparative oncology DNA sequencing of canine T cell lymphoma via human hotspot panel.

T-cell lymphoma (TCL) is an uncommon and aggressive form of human cancer. Lymphoma is the most common hematopoietic tumor in canines (companion animals), with TCL representing approximately 30% of diagnoses. Collectively, the canine is an appealing model for cancer research given the spontaneous occurrence of cancer, intact immune system, and phytogenetic proximity to humans. We sought to establish mutational congruence of the canine with known human TCL mutations in order to identify potential actionable oncogenic pathways. Following pathologic confirmation, DNA was sequenced in 16 canine TCL (cTCL) cases using a custom Human Cancer Hotspot Panel of 68 genes commonly mutated in human TCL. Sequencing identified 4,527,638 total reads with average length of 229 bases containing 346 unique variants and 1,474 total variants; each sample had an average of 92 variants. Among these, there were 258 germline and 32 somatic variants. Among the 32 somatic variants there were 8 missense variants, 1 splice junction variant and the remaining were intron or synonymous variants. A frequency of 4 somatic mutations per sample were noted with >7 mutations detected in MET, KDR, STK11 and BRAF. Expression of these associated proteins were also detected via Western blot analyses. In addition, Sanger sequencing confirmed three variants of high quality (MYC, MET, and TP53 missense mutation). Taken together, the mutational spectrum and protein analyses showed mutations in signaling pathways similar to human TCL and also identified novel mutations that may serve as drug targets as well as potential biomarkers.

Analyses of publicly available genomics resources define FGF-2-expressing bladder carcinomas as EMT-prone, proliferative tumors with low mutation rates and high expression of CTLA-4, PD-1 and PD-L1.

FGF-2 is overexpressed in a subset of invasive bladder carcinomas and its overexpression correlates with poor prognosis. Analyses of publicly available databases addressing the molecular mechanisms that may be responsible for the poor prognosis of these tumors, revealed that FGF-2 expression correlates positively with the expression of EMT-promoting transcription factors and with changes in gene expression that are characteristic of EMT. The same analyses also revealed that FGF-2 correlates negatively with the expression, mutation and copy number variations of FGFR-3, all of which are associated with non-invasive bladder carcinomas. Finally, they showed that FGF-2 expression correlates with the expression of FGFR-1, the expression of the IIIc variant of FGFR-2 and with the expression of Akt3. The latter observation is significant because our earlier studies had shown that Akt3 regulates FGFR-2 alternative splicing, shifting the balance toward the IIIc relative to the IIIb FGFR-2 splice variant. Since the IIIc variant is recognized by FGF-2, while the IIIb variant is not, we conclude that Akt3 may facilitate the FGF-2 response. FGF-2 is known to promote the expression of KDM2B, which functions in concert with EZH2 to repress the EZH2-targeting microRNA miR-101, activating a switch, which stably upregulates EZH2. TCGA data showing a correlation between KDM2B and EZH2 expression and Oncomine data, showing a correlation between KDM2B and tumor progression, strongly support the role of the FGF-2/KDM2B/miR-101/EZH2 pathway in bladder cancer. These observations combined, suggest a model according to which FGF-2 induces EMT, cell proliferation and cancer stem cell self-renewal by coupling the Akt3 and KDM2B-controlled pathways outlined above, in bladder carcinomas. Further analyses of publicly-available databases, revealed that FGF-2-expressing bladder carcinomas carry fewer genetic alterations and they tend to express high levels of CTLA-4, PD-1 and PD-L1, which suggests immune blockade by checkpoint activation. EMT, enhanced proliferation and immune checkpoint activation combined, may be responsible for the poor prognosis of FGF-2-expressing bladder carcinomas.

Diagnostic performance of the urinary canine calgranulins in dogs with lower urinary or urogenital tract carcinoma.

BACKGROUND: Onset of canine transitional cell carcinoma (TCC) and prostatic carcinoma (PCA) is usually insidious with dogs presenting at an advanced stage of the disease. A biomarker that can facilitate early detection of TCC/PCA and improve patient survival would be useful. S100A8/A9 (calgranulin A/B or calprotectin) and S100A12 (calgranulin C) are expressed by cells of the innate immune system and are associated with several inflammatory disorders. S100A8/A9 is also expressed by epithelial cells after malignant transformation and is involved in the regulation of cell proliferation and metastasis. S100A8/A9 is up-regulated in human PCA and TCC, whereas the results for S100A12 have been ambiguous. Also, the urine S100A8/A9-to-S100A12 ratio (uCalR) may have potential as a marker for canine TCC/PCA. Aim of the study was to evaluate the diagnostic accuracy of the urinary S100/calgranulins to detect TCC/PCA in dogs by using data and urine samples from 164 dogs with TCC/PCA, non-neoplastic urinary tract disease, other neoplasms, or urinary tract infections, and 75 healthy controls (nested case-control study). Urine S100A8/A9 and S100A12 (measured by species-specific radioimmunoassays and normalized against urine specific gravity [S100A8/A9USG; S100A12USG], urine creatinine concentration, and urine protein concentration and the uCalR were compared among the groups of dogs. RESULTS: S100A8/A9USG had the highest sensitivity (96%) and specificity (66%) to detect TCC/PCA, with specificity reaching 75% after excluding dogs with a urinary tract infection. The uCalR best distinguished dogs with TCC/PCA from dogs with a urinary tract infection (sensitivity: 91%, specificity: 60%). Using a S100A8/A9USG ≥ 109.9 to screen dogs ≥6 years of age for TCC/PCA yielded a negative predictive value of 100%. CONCLUSIONS: S100A8/A9USG and uCalR may have utility for diagnosing TCC/PCA in dogs, and S100A8/A9USG may be a good screening test for canine TCC/PCA.

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.

UNLABELLED: 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 IMPLICATIONS: 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.

NDY1/KDM2B functions as a master regulator of polycomb complexes and controls self-renewal of breast cancer stem cells.

The JmjC domain histone H3K36me2/me1 demethylase NDY1/KDM2B is overexpressed in various types of cancer. Here we show that knocking down NDY1 in a set of 10 cell lines derived from a broad range of human tumors inhibited their anchorage-dependent and anchorage-independent growth by inducing senescence and/or apoptosis in some and by inhibiting G1 progression in all. We further show that the knockdown of NDY1 in mammary adenocarcinoma cell lines decreased the number, size, and replating efficiency of mammospheres and downregulated the stem cell markers ALDH and CD44, while upregulating CD24. Together, these findings suggest that NDY1 is required for the self-renewal of cancer stem cells and are in agreement with additional findings showing that tumor cells in which NDY1 was knocked down undergo differentiation and a higher number of them is required to induce mammary adenocarcinomas, upon orthotopic injection in animals. Mechanistically, NDY1 functions as a master regulator of a set of miRNAs that target several members of the polycomb complexes PRC1 and PRC2, and its knockdown results in the de-repression of these miRNAs and the downregulation of their polycomb targets. Consistent with these observations, NDY1/KDM2B is expressed at higher levels in basal-like triple-negative breast cancers, and its overexpression is associated with higher rates of relapse after treatment. In addition, NDY1-regulated miRNAs are downregulated in both normal and cancer mammary stem cells. Finally, in primary human breast cancer, NDY1/KDM2B expression correlates negatively with the expression of the NDY1-regulated miRNAs and positively with the expression of their PRC targets.

Evaluation of hypoxia in a feline model of head and neck cancer using 64Cu-ATSM positron emission tomography/computed tomography.

BACKGROUND: Human and feline head and neck squamous cell carcinoma (HNSCC) share histology, certain molecular features, as well as locally aggressive and highly recurrent clinical behavior. In human HNSCC, the presence of significant hypoxia within these tumors is considered an important factor in the development of a more aggressive phenotype and poor response to therapy. We hypothesized that feline head and neck tumors, particularly HNSCC, would exhibit hypoxia and that 64Cu-diacetyl-bis(N4-methylthiosemicarbazone) (Cu-ATSM) positron emission tomography/computed tomography (PET/CT) would permit detection of intratumoral hypoxia. METHODS: 12 cats with measureable head and neck tumors were given 64Cu-ATSM and iodinated contrast for PET/CT scan. The presence or absence of hypoxia was also assessed using an intratumoral fluorescent life-time probe to quantitate pO2 and pimonidazole immunohistochemical staining in biopsy specimens. In two cats, intratumoral O2 and 64Cu-ATSM uptake was measured before and after treatment with anti-angiogenic agents to determine the effect of these agents on hypoxia. RESULTS: Eleven of twelve feline tumors demonstrated significant 64Cu-ATSM uptake, regardless of malignant or benign etiology. The presence (and absence) of hypoxia was confirmed using the fluorescent O2 detection probe in nine tumors, and using pimonidazole staining in three tumors. Squamous cell carcinomas (HNSCC) demonstrated the highest degree of hypoxia, with Tmax/M ratios ranging from 4.3 to 21.8. Additional non-neoplastic tissues exhibited 64Cu-ATSM uptake suggestive of hypoxia including reactive draining lymph nodes, non-malignant thyroid pathology, a tooth root abscess, and otitis media. In two cats with HNSCC that received anti-vascular agents, the pattern of 64Cu-ATSM uptake was altered after treatment, demonstrating the potential of the feline model to study the modulation of tumor oxygenation. CONCLUSION: Feline HNSCC serves as a clinically relevant model for the investigation of intratumoral hypoxia including its measurement, modulation and targeting.

Conservation of avian germplasm by xenogeneic transplantation of spermatogonia from sexually mature donors.

Approximately 12.5% of all 9,920 extant bird species in the world are threatened with extinction, and yet conservation efforts through natural breeding of captive species continue to encounter difficulties. However, sperm cryopreservation and artificial insemination offer potential benefits over natural breeding, but their applicability is still limited in nondomestic species. In this study, we aimed to exploit the potential of germ cell xenotransplantation as an alternative tool for preserving germplasm of endangered birds. The study was designed to investigate whether transfer of either spermatogonia-enriched cell fraction (SEF) or crude testicular cell fraction (CTF) from adult Japanese quails (as a model for wild species) would result in recolonization of gamma-irradiated gonads of adult recipient chickens. One month after transplantation, 75% of recipients injected with SEF and 25% of recipients injected with CTF resumed spermatogenesis. However, it took more than 3 months for 33% of the negative controls to resume marginal production of sperm. Some SEF recipients produced more spermatozoa bearing head morphology compared with donor controls. DNA analysis using quail-specific primers did not detect donor's DNA in these recipients' semen. However, 6 months after xenotransplantation, presence of quail germ cells was demonstrated by polymerase chain reaction and by immunohistochemistry in 1 rooster injected with SEF. These findings indicate that spermatogonia from adult quails were capable of colonizing immunocompetent testis of adult chickens but failed to produce sufficient sperm. Despite this limitation, the present approach represents a potential conservation tool that may be used to rescue germ cells of endangered adult male birds.

Use of propofol for induction of anesthesia in dogs undergoing definitive radiation therapy: 31 cases (2006-2009).

OBJECTIVE: To evaluate changes in serial hemograms and serum biochemical profiles in tumor-bearing dogs undergoing daily anesthesia with propofol as an induction agent for radiation therapy. DESIGN: Retrospective case series. ANIMALS: 31 dogs with cutaneous or subcutaneous malignancies over the trunk or limbs. PROCEDURES: Radiation therapy consisted of 18 daily treatments administered Monday through Friday over a period of 24 days. Propofol was administered IV to effect for induction of anesthesia. Complete blood count and serum biochemical data were generated at the beginning, middle, and end of radiation therapy and compared to identify changes over time via either a repeated-measures ANOVA or Friedman test. RESULTS: Leukocyte and platelet parameters did not differ significantly over time. Calculated Hct, erythrocyte count, hemoglobin concentration, and mean corpuscular hemoglobin concentration decreased overtime, whereas mean corpuscular volume increased overtime. CONCLUSIONS AND CLINICAL RELEVANCE: Dogs receiving propofol for induction of anesthesia and radiation therapy had a decrease in RBC count, although these changes were not determined to be of clinical importance in this patient population. The cause of these alterations was not immediately apparent. Propofol appeared to be a safe choice for induction of anesthesia in dogs during daily radiation therapy.

Use of three-dimensional conformal radiation therapy for treatment of a heart base chemodectoma in a dog.

CASE DESCRIPTION: A 9-year-old spayed female mixed-breed dog was evaluated because of a progressively worsening, nonproductive cough and gagging of 1 year's duration. CLINICAL FINDINGS: Physical examination results were unremarkable. A cranial mediastinal mass was identified at the heart base with 3-view thoracic radiography. A CT scan of the thorax revealed an invasive mass surrounding major vessels at the heart base that was not considered surgically resectable. Thoracoscopic biopsy specimens of the cranial mediastinal mass were obtained, and histologic evaluation revealed that the tumor was a chemodectoma. TREATMENT AND OUTCOME: On the basis of results of the CT scan, a 3-D conformal radiation therapy plan was generated with computer treatment-planning software. The patient was treated with external beam radiation therapy; a 6-MV linear accelerator was used to deliver a prescribed dose of 57.5 Gy in twenty-three 2.5-Gy fractions. The cough improved following radiation therapy. Prior to treatment, the tumor volume was calculated to be 126.69 cm(3). Twenty-five months following radiation therapy, a follow-up CT scan was performed and there was a >50% reduction in tumor volume at that time. Disease progression causing pericardial, pleural, and peritoneal effusion and syncopal episodes occurred 32 months following radiation therapy, which were treated with pericardectomy and additional radiation therapy. The dog was still alive and doing well 42 months following initial radiation treatment. CLINICAL RELEVANCE: Conformal radiation therapy provided an additional treatment option for a nonresectable heart base chemodectoma in the dog of this report; conformal radiation therapy was reasonably tolerable and safe.

Initial evaluation of safety of wide-field irradiation in the treatment of hematopoietic neoplasia in the cat.

Localized radiation therapy is well tolerated in cats with confined tumors; however, the use of wide-field radiation therapy to treat disseminated neoplasia has not been evaluated systematically in this species. Wide-field external beam radiation therapy, which we define as irradiation of cranial or caudal halves of the body either individually or sequentially, was undertaken as an experimental option to treat cats with either chemotherapy-refractory or naive hematopoietic neoplasia considered to have a poor prognosis. Fifteen cats with hematopoietic malignancies received wide-field external beam radiation therapy between 2003 and 2006. Cats received 8 Gy delivered in 4 Gy fractions with 60Co photons. Treatment-related toxicity was scored according to criteria established by the Veterinary Cooperative Oncology Group. Animals without preexisting abnormalities on hemograms exhibited no or mild (Grade 1 or 2) hematopoietic toxicity. Although most cats (14 of 15) had preexisting gastrointestinal (GI) signs, these signs were stable (29%) or improved (42%) following irradiation. Worsening GI signs following irradiation occurred transiently in two cats and in association with progressive disease in two others. No pulmonary, renal, hepatic, or dermatologic toxicities were detected. In summary, wide-field external beam radiation therapy can be administered safely to, and may provide therapeutic benefit for, cats with disseminated hematopoietic neoplasia.

Treatment of an amelanotic melanoma using radiation therapy in a lesser Madagascar hedgehog tenrec (Echinops telfairi).

A 15-yr-old, male lesser Madagascar hedgehog tenrec (Echinops telfairi) presented with a mass caudal to the right ear. Cytology suggested a sarcoma. Surgical removal was attempted. Histology was consistent with a soft tissue sarcoma. The mass recurred within 331 days post operation. Radiation therapy was initiated. Computed tomography was used for staging in conjunction with three-dimensional computerized treatment planning software to permit accurate lesion localization and to optimize normal tissue sparing. A total dose of 6,480 cGy was administered in 24 fractions over 46 days. Transient hind limb paresis developed during the course of the radiation therapy, but resolved after 7 days with prednisone treatment. Minimal acute radiation toxicity was observed. The mass responded with at least a 90% reduction in volume following radiation treatment. The animal survived 266 days from the initiation of treatment. On necropsy, a small mass and granulation tissue were found at the site of the initial neoplasm, indicating good regional control of the tumor; however, extensive metastases to the spleen and liver were present. Immunohistochemically, the original, recurrent, and metastatic populations were strongly positive for HMB 45 and weakly positive for S-100, and the final diagnosis was metastatic amelanotic melanoma.

Microsatellite instability in canine mammary gland tumors.

BACKGROUND: Genomic instability is a hallmark of cancer and may be required for the accumulation of cancer-causing mutations within cells. One form of genomic instability occurs in tandem nucleotide repeats and is known as microsatellite instability (MSI). HYPOTHESIS: We hypothesized that MSI can be observed in canine mammary gland tumors (MGT) and represents a potential carcinogenic mechanism in dogs. ANIMALS: Thirty-five dogs with MGTs and 9 dogs with other tumors were recruited from the University of Minnesota Veterinary Medical Center and referring veterinary clinics. METHODS: A panel of 21 canine microsatellite (MS) markers was amplified by polymerase chain reaction (PCR) from deoxyribonucleic acid obtained from blood and from fresh or formalin-fixed, paraffin-embedded tumor tissues. PCR products were evaluated by using capillary electrophoresis, and the chromatograms were analyzed by using genotyping software. MS genotypes obtained from fresh and formalin-fixed tumor tissues were compared, as were MS genotypes from normal tissue and tumor tissue. RESULTS: Genotypes obtained from formalin-fixed and fresh tissues were identical for all MS in 9 tumors evaluated, suggesting excellent concordance between the 2 sample types. For the 35 canine mammary tumors evaluated, 13 (37%) had stable genotypes; 22 (63%) exhibited aberrations in 1 or 2 MS; and 4 tumors (11%) demonstrated high-level instability, with aberrations in 29 to 61% of MS. CONCLUSIONS AND CLINICAL IMPORTANCE: Although some low-level MSI often is observed, high-level MSI is an infrequent finding in canine mammary tumors. Further evaluations are required to better characterize this phenomenon and to determine its relevance to canine carcinogenesis.

Intracranial glioblastoma models in preclinical neuro-oncology: neuropathological characterization and tumor progression.

Although rodent glioblastoma (GBM) models have been used for over 30 years, the extent to which they recapitulate the characteristics encountered in human GBMs remains controversial. We studied the histopathological features of dog GBM and human xenograft GBM models in immune-deficient mice (U251 and U87 GBM in nude Balb/c), and syngeneic GBMs in immune-competent rodents (GL26 cells in C57BL/6 mice, CNS-1 cells in Lewis rats). All GBMs studied exhibited neovascularization, pleomorphism, vimentin immunoreactivity, and infiltration of T-cells and macrophages. All the tumors showed necrosis and hemorrhages, except the U87 human xenograft, in which the most salient feature was its profuse neovascularization. The tumors differed in the expression of astrocytic intermediate filaments: human and dog GBMs, as well as U251 xenografts expressed glial fibrillary acidic protein (GFAP) and vimentin, while the U87 xenograft and the syngeneic rodent GBMs were GFAP(-) and vimentin(+). Also, only dog GBMs exhibited endothelial proliferation, a key feature that was absent in the murine models. In all spontaneous and implanted GBMs we found histopathological features compatible with tumor invasion into the non-neoplastic brain parenchyma. Our data indicate that murine models of GBM appear to recapitulate several of the human GBM histopathological features and, considering their reproducibility and availability, they constitute a valuable in vivo system for preclinical studies. Importantly, our results indicate that dog GBM emerges as an attractive animal model for testing novel therapies in a spontaneous tumor in the context of a larger brain.

Scheduling of radiation with angiogenesis inhibitors anginex and Avastin improves therapeutic outcome via vessel normalization.

PURPOSE: To test whether a direct antiangiogenic peptide (anginex) and a vascular endothelial growth factor antibody (bevacizumab, Avastin) can transiently normalize vasculature within tumors to improve oxygen delivery, alleviate hypoxia, and increase the effect of radiation therapy. EXPERIMENTAL DESIGN: Tumor oxygenation levels, microvessel density and pericyte coverage were monitored in three different solid tumor models (xenograft human ovarian carcinoma MA148, murine melanoma B16F10, and murine breast carcinoma SCK) in mice. Multiple treatment schedules were tested in these models to assess the influence on the effect of radiation therapy. RESULTS: In all three tumor models, we found that tumor oxygenation levels, monitored daily in real time, were increased during the first 4 days of treatment with both anginex and bevacizumab. From treatment day 5 onward, tumor oxygenation in treated mice decreased significantly to below that in control mice. This "tumor oxygenation window" occurred in all three tumor models varying in origin and growth rate. Moreover, during the treatment period, tumor microvessel density decreased and pericyte coverage of vessels increased, supporting the idea of vessel normalization. We also found that the transient modulation of tumor physiology caused by either antiangiogenic therapy improved the effect of radiation treatment. Tumor growth delay was enhanced when single dose or fractionated radiotherapy was initiated within the tumor oxygenation window as compared with other treatment schedules. CONCLUSIONS: The results are of immediate translational importance because the clinical benefits of bevacizumab therapy might be increased by more precise treatment scheduling to ensure radiation is given during periods of peak radiosensitivity. The oxygen elevation in tumors by non-growth factor-mediated peptide anginex suggests that vessel normalization might be a general phenomenon of agents directed at disrupting the tumor vasculature by a variety of mechanisms.

Urinary biomarkers to assess exposure of cats to environmental tobacco smoke.

OBJECTIVE: To evaluate the use of urinary biomarkers to assess exposure of cats to environmental tobacco smoke (ETS). ANIMALS: 61 healthy client-owned cats (19 from households in which smoking was reported and 42 from households in which there was no smoking). PROCEDURES: Urine samples were obtained from each cat and assayed for total nicotine (nicotine plus nicotine glucuronide) and total cotinine (cotinine plus cotinine glucuronide) content by use of gas chromatography-mass spectrometry. In addition, total urinary content of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL), a major metabolite of the tobacco-specific nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, was measured by use of gas chromatography with nitrosamine-selective detection. RESULTS: Cats from households in which smoking was reported had significantly higher concentrations of total nicotine (70.4 ng/mL), total cotinine (8.53 ng/mL), and total NNAL (0.0562 pmol/mL) in urine, compared with concentrations for cats that lived in households in which there was no smoking (4.89 ng/mL, 0.74 ng/mL, and 0.0182 pmol/mL, respectively). CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of these data provided biochemical evidence of exposure to ETS and uptake of tobacco-specific carcinogens by cats that live in households with smokers. Biomarkers could facilitate investigation of the health effects of ETS in cats and other species.