Canine Carcinoma Research Articles

KRAS Mutations in Canine and Feline Pancreatic Acinar Cell Carcinoma

Companion animals may serve as valuable models for studying human cancers. Although KRAS is the most commonly mutated gene in human ductal pancreatic cancers (57%), with mutations frequently occurring at codons 12, 13 and 61, human pancreatic acinar cell carcinomas (ACCs) lack activating KRAS mutations. In the present study, 32 pancreatic ACC samples obtained from 14 dogs and 18 cats, including seven metastases, were analyzed for six common activating KRAS mutations located in codons 12 (n=5)and 13 (n=1) using Sequenom MassARRAY. No KRAS mutations were found, suggesting that, similar to human pancreatic ACC, KRAS mutations do not play a critical role in feline or canine pancreatic ACC. Due to the similarity of the clinical disease in dogs and cats to that of man, this study confirms that companion animals offer potential as a suitable model for investigating this rare subtype of pancreatic carcinoma.

Identification of occult micrometastases and isolated tumour cells within regional lymph nodes of previously diagnosed non-metastatic (stage 0) canine carcinomas.

Metastatic dissemination of carcinomas to lymph nodes impacts prognosis and treatment recommendations in human and veterinary medicine. Routine histopathologic evaluation of regional lymph nodes involves haematoxylin and eosin (H&E) staining to identify intra-nodal neoplastic cells; however, identification of small volume metastases (micrometastases and individual tumour cells) may be missed without the aid of immunohistochemistry or additional step-sections. The aim of this study was to identify occult carcinoma metastases in previously diagnosed non-metastatic lymph nodes using step-sections and pancytokeratin (panCK) immunohistochemistry. Samples from 20 regional lymph nodes diagnosed as non-metastatic were serially sectioned and evaluated with panCK. Of these, 25% (n = 5) contained micrometastases (n = 1) or isolated tumour cells (n = 4). This study demonstrates the increased efficacy of serial step-sections combined with panCK immunohistochemistry to identify small volume metastases in regional lymph nodes. The prognostic significance of micrometastases and isolated tumour cells in regional lymph nodes warrants further investigation in veterinary medicine.

Abstract A07: Spontaneous canine mammary cancers: A much-needed model for human basal-like breast cancer and an ideal system to understand myoepithelial cells

Abstract Spontaneous canine mammary cancer represents an excellent model of human breast cancer but is greatly understudied. To better utilize this valuable resource, we performed the first comprehensive characterization of the genome, transcriptome and epigenome of 12 canine mammary cancer cases, including 7 simple carcinomas and 4 complex carcinomas (1). Simple carcinomas, which histologically match human breast carcinomas, harbor extensive genomic aberrations, many of which faithfully recapitulate key features of human breast cancer. Notably, these tumors closely cluster with human basal-like breast carcinomas from TCGA (2), but not with other intrinsic subtypes, in PAM50 classification with human breast carcinomas. Furthermore, these tumors match the basal-like cancer profile, including MYC amplification, PTEN deletion, BRCA1 mutation, etc. Our results indicate canine simple carcinomas could serve as a much-needed spontaneous cancer model of basal-like breast cancer by effectively bridging the gap between preclinical research and human trials, speeding up drug discovery for the worst subtype of breast cancer. Canine complex carcinomas, characterized by proliferation of both luminal and myoepithelial cells (rare in human breast cancer), appear to lack genomic abnormalities. Instead, these tumors have ~35 chromatin-modification genes downregulated, and are abnormally enriched with active histone modification H4-acetylation while depleted with repressive histone modification H3K9me3. Our findings indicate that these tumors likely originate from epigenomic alterations instead of genomic lesions. Canine complex carcinomas offer an ideal system to study myoepithelial cells, the second major yet significantly understudied cell lineage of the mammary gland.

Abstract 5142: A naturally occurring model for gastric cancer

Abstract Gastric cancer is the fourth most common cancer and the second leading cause of cancer related deaths. While there are increasing data characterizing the molecular features and defining potential targets for gastric carcinoma, preclinical animal models that recapitulate the human disease are limited. We have developed a number of resources to permit the characterization of spontaneously occurring canine gastric cancer which may provide a useful resource to understand gastric cancer carcinogenesis, its prevention and treatment. While gastric carcinoma is reportedly uncommon in dogs, certain breeds have significantly increased risk. To study this disease, we have established a database and tissue repository. Our goal has been to characterize canine gastric carcinoma clinically, histologically, and molecularly to determine its comparative value as a model for the human disease. Recently, we have performed a histologic review of 50 canine gastric carcinomas and have found that the canine disease is comprises largely of diffuse type gastric carcinoma and is enriched in the signet ring variant. We report for the first time a technique for culturing primary gastric cancer from affected dogs. Gastric cancer tissue specimens collected from spontaneously occurring tumors in dogs were disaggregated with collagenase and cells were grown in mammary epithelial growth media with or without 5% FBS. Four different cell lines were derived from tumors of a Labrador mix (GC1), a Basset hound (GC2), a Bouvier de Flandres (GC3) and a mixed breed (GC4). Early passages of all cell lines were able to form colonies when grown in soft agar. Different growth patterns were observed when cells were cultured with versus without serum. Serum treated cells tend to be fast growing, fibroblastic in appearance and senesce within 10 to 18 passages and these may represent cancer associated fibroblasts or mesenchymal differentiation of cancer cells. However, cells grown in mammary epithelial growth media without serum tend to form spheres that grow well when transferred to ultra-low attachment plate and form extensions when grown in matrigel. That semi-attached growth behavior is consistent with that reported for some human gastric cancer cell lines. Canine gastric cancer cell lines provide a new resource for the characterization of this spontaneous model that recapitulates diffuse, signet ring cell gastric carcinoma. Citation Format: Manar A. AbdelMageed, Monica Betancur-Boissel, Parthena Foltopoulou, Sureshkumar Muthupalani, James G. Fox, Elizabeth A. McNiel. A naturally occurring model for gastric cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5142. doi:10.1158/1538-7445.AM2015-5142

Napsin A and Thyroid Transcription Factor‐1 Immunohistochemistry in the Diagnosis of Canine Pulmonary Carcinomas

Targeted cancer therapy demands accurate diagnosis of primary pulmonary carcinomas and their distinction from metastatic tumors in the lung. Thyroid transcription factor-1 (TTF-1) is a commonly use...

Dose painting based on tumor uptake of Cu-ATSM and FDG: a comparative study.

BackgroundHypoxia and increased glycolytic activity of tumors are associated with poor prognosis. The purpose of this study was to investigate differences in radiotherapy (RT) dose painting based on the uptake of 2-deoxy-2-[18 F]-fluorodeoxyglucose (FDG) and the proposed hypoxia tracer, copper(II)diacetyl-bis(N4)-methylsemithiocarbazone (Cu-ATSM) using spontaneous clinical canine tumor models.MethodsPositron emission tomography/computed tomography scans of five spontaneous canine sarcomas and carcinomas were obtained; FDG on day 1 and 64Cu-ATSM on day 2 and 3 (approx. 3 and 24 hours pi.). Sub-volumes for dose escalation were defined by a threshold-based method for both tracers and five dose escalation levels were formed in each sub-volume. Volumetric modulated arc therapy plans were optimized based on the dose escalation regions for each scan for a total of three dose plans for each dog. The prescription dose for the GTV was 45 Gy (100%) and it was linearly escalated to a maximum of 150%. The correlations between dose painting plans were analyzed with construction of dose distribution density maps and quality volume histograms (QVH). Correlation between high-dose regions was investigated with Dice correlation coefficients.ResultsComparison of dose plans revealed varying degree of correlation between cases. Some cases displayed a separation of high-dose regions in the comparison of FDG vs. 64Cu-ATSM dose plans at both time points. Among the Dice correlation coefficients, the high dose regions showed the lowest degree of agreement, indicating potential benefit of using multiple tracers for dose painting. QVH analysis revealed that FDG-based dose painting plans adequately covered approximately 50% of the hypoxic regions.ConclusionRadiotherapy plans optimized with the current approach for cut-off values and dose region definitions based on FDG, 64Cu-ATSM 3 h and 24 h uptake in canine tumors had different localization of the regional dose escalation levels. This indicates that 64Cu-ATSM at two different time-points and FDG provide different biological information that has to be taken into account when using the dose painting strategy in radiotherapy treatment planning.

Molecular homology and difference between spontaneous canine mammary cancer and human breast cancer.

Spontaneously occurring canine mammary cancer represents an excellent model of human breast cancer, but is greatly understudied. To better use this valuable resource, we performed whole-genome sequencing, whole-exome sequencing, RNA-seq, and/or high-density arrays on twelve canine mammary cancer cases, including seven simple carcinomas and four complex carcinomas. Canine simple carcinomas, which histologically match human breast carcinomas, harbor extensive genomic aberrations, many of which faithfully recapitulate key features of human breast cancer. Canine complex carcinomas, which are characterized by proliferation of both luminal and myoepithelial cells and are rare in human breast cancer, seem to lack genomic abnormalities. Instead, these tumors have about 35 chromatin-modification genes downregulated and are abnormally enriched with active histone modification H4-acetylation, whereas aberrantly depleted with repressive histone modification H3K9me3. Our findings indicate the likelihood that canine simple carcinomas arise from genomic aberrations, whereas complex carcinomas originate from epigenomic alterations, reinforcing their unique value. Canine complex carcinomas offer an ideal system to study myoepithelial cells, the second major cell lineage of the mammary gland. Canine simple carcinomas, which faithfully represent human breast carcinomas at the molecular level, provide indispensable models for basic and translational breast cancer research.

Host-cell specificity and transcytosis of nontoxic nonhemagglutinin protein of botulinum neurotoxin serotype D

Serotype D botulinum toxin (BoNT) complex (TC), a causative agent of foodborne botulism in animals, traverses the gastrointestinal tract and circulation, eventually becoming localized in neuromuscular junctions, where the serotype D BoNT cleaves SNARE substrate synaptobrevin II involved in neurotransmitter release. During this process, BoNT must pass through cells, thus from the intestinal lumen to the cells of the intestinal tract and blood vessels. The botulinum TC is formed by association of the BoNT with at least one nontoxic protein, which may be a nontoxic nonhemagglutinin (NTNHA). In this work, we examined the binding and transcytosis of serotype D NTNHA protein in epithelial and endothelial cells to clarify the role played by the protein in toxin delivery. Our studies showed that NTNHA bound to and transcytosed across rat intestinal epithelial (IEC-6) and bovine aortic endothelial (BAEC) cells. While NTNHA also bound to canine renal (MDCK) or human colon carcinoma (Caco-2) cells, but it did not traverse across MDCK or Caco-2 cells. Such specificity of NTNHA protein transcytosis may explain why only some animals are sensitive to botulinum toxin. The sensitivity depends on the toxin serotype in play, and the route of toxin delivery.

The Dog as a Natural Animal Model for Study of the Mammary Myoepithelial Basal Cell Lineage and its Role in Mammary Carcinogenesis

Basal-like tumours constitute 2-18% of all human breast cancers (HBCs). These tumours have a basal myoepithelial phenotype and it has been hypothesized that they originate from either myoepithelial cells or mammary progenitor cells. They are heterogeneous in morphology, clinical presentation, outcome and response to therapy. Canine mammary carcinomas (CMCs) have epidemiological and biological similarities to HBCs, are frequently biphasic and are composed of two distinct neoplastic populations (epithelial and myoepithelial). The present study evaluates the potential of CMCs as a natural model for basal-like HBCs. Single and double immunohistochemistry was performed on serial sections of 10 normal canine mammary glands and 65 CMCs to evaluate expression of cytokeratin (CK) 8/18, CK5, CK14, α-smooth muscle actin (SMA), calponin (CALP), p63 and vimentin (VIM). The tumours were also evaluated for Ki67 and human epidermal growth factor receptor (HER)-2 expression. A hierarchical model of cell differentiation was established, similar to that for the human breast. We hypothesized that progenitor cells (CK5(+), CK14(+), p63(+) and VIM(+)) differentiate into terminally-differentiated luminal glandular (CK8/18(+)) and myoepithelial (CALP(+), SMA(+) and VIM(+)) cells via intermediary luminal glandular cells (CK5(+), CK14(+) and CK8/CK18(+)) and intermediary myoepithelial cells (CK5(+), CK14(+), p63(+), SMA(+), CALP(+) and VIM(+)). Neoplastic myoepithelial cells in canine complex carcinomas had labelling similar to that of terminally-differentiated myoepithelial cells, while those of carcinomas-and-malignant myoepitheliomas with a more aggressive biological behaviour (i.e. higher frequency of vascular/lymph node invasion and visceral metastases and higher risk of tumour-related death) were comparable with intermediary myoepithelial cells and had significantly higher Ki67 expression. The majority of CMCs examined were negative for expression of HER-2. The biphasic appearance of CMCs with involvement of the myoepithelial component in different stages of cell differentiation may help to define the role of myoepithelial cells in the mammary carcinogenetic process and the heterogeneous nature of basal-like HBCs.

Prognostic significance of histologic features in canine renal cell carcinomas: 70 nephrectomies.

The prognostic significance of histologic and clinical features was evaluated in a retrospective study of 70 dogs treated with nephrectomy for renal cell carcinoma. Dogs presenting with hematuria and cachexia had significantly decreased overall and tumor-specific survival. Mitotic index (MI), nuclear size, nuclear pleomorphism, tumor differentiation, invasiveness, Fuhrman nuclear grade, and clear cell morphology were significantly associated with survival times (overall and tumor specific) in univariate analyses. A multivariate Cox proportional hazards model was constructed using stepwise selection to evaluate potential histologic predictor variables. This multivariate analysis revealed MI, defined as the number of mitotic figures in ten 400× fields, as the sole independent prognostic variable. Median survival for dogs with an MI >30 was 187 days compared with 1184 days for dogs with an MI of <10. Dogs with an intermediate MI of 10 to 30 had a median survival of 452 days. Canine renal carcinomas were categorized into the following subtypes based on histologic features and histochemical and immunohistochemical staining: (1) clear cell, (2) chromophobe, (3) papillary, and (4) multilocular cystic renal cell carcinomas. Clear cell carcinoma was diagnosed in 6 of 70 (9%) canine tumors and was associated with a significantly decreased median survival time. Papillary carcinomas were identified in 15 of 70 tumors (21%), chromophobe in 6 of 70 (9%), and the multilocular cystic variant of canine renal cell carcinoma in 3 of 70 tumors (4%). These findings facilitate uniform categorization of canine renal cell carcinoma and provide veterinary pathologists with criteria to determine prognostic information.

Cytotoxic Effects of Loperamide Hydrochloride on Canine Cancer Cells

Loperamide is a peripheral opiate agonist that can cause apoptosis and G2/M arrest in human cancer cell lines and may sensitize cells to chemotherapy. The objectives of this study were to investigate the effects of loperamide on viability, apoptosis and cell cycle kinetics in canine cancer cells and to establish whether the drug sensitizes cells to doxorubicin. Cell viability was assessed using Alamar Blue. Cell death and cell cycle were studied using flow cytometry with 7-Aminoactinomycin-D (7-AAD) and propidium iodide (PI), respectively. Loperamide decreased cell viability in a dose-dependent fashion and was most effective against canine osteosarcoma cells. In all cell lines, it induced a dose and time dependent apoptosis and resulted in accumulation in G0/G1. When co-incubated with doxorubicin, loperamide induced a synergistic cell kill in canine carcinoma cells. Investigation is warranted into the role of loperamide in the treatment of canine cancer.

Abstract P6-12-16: Treatment with indol-3-carbinol (I3C) in a mice xenograft model of canine breast carcinoma alter hormone metabolism and produce liver metastases

Abstract Indol-3-carbinol (I3C) is a chemical component found mainly in the cruciferous family lants (i.e. broccoli, cabbage, cauliflower, etc.). I3C is considered a potential anticancer agent that is naturally present in the diet and could prevents the development of certain tumors, activating tumor suppressor genes, genes involved in apoptosis and detoxifying genes. It has been observed in vitro that suppresses cell proliferation and induces apoptosis in some breast cancers. I3C is also estrogen receptor (ER) and androgen receptor (AR)Antagonist. Therefore, studies using I3C in breast cancer animal models for its action as a preventive or therapeutic substance have started. There are no data on the influence of I3C in human and/or spontaneous or experimental canine inflammatory breast cancers, that has shown to have distinct pathogenic mechanisms. The aim of this study was to analyze the effect of I3C administration at a comparable dose used as preventive in humans in a xenograft model of canine inflammatory carcinoma established in SCID mice. Eighteen mice were used as controls and 13 mice were treated with I3C dose 150 mg/kg/day. Tumor cell proliferation was decreased in the I3C-treated xenografts (lower Ki-67 index, p &amp;lt;0.001), but neoplasms were more frequently ulcerated (p = 0.028), and mice had a higher number of emboli in dermis (p = 0.012) (characteristic of inflammatory breast carcinoma) and liver metastases (p = 0.05). In the treated group the presence of a subpopulation of neoplastic lipid-rich cells was characteristic (p = 0.001) togetehr with a higher content of intratumor androgens (p = 0.02) and serum steroid hormone (p &amp;lt;0 05). These results indicate that treatment with I3C, as administered, is not suitable for inflammatory breast carcinoma. This study was funded by the research project of the Ministry of Science and Innovation SAF2009-10572. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-12-16.

1,25-Dihydroxyvitamin D3 and its analogues increase catalase at the mRNA, protein and activity level in a canine transitional carcinoma cell line.

Antioxidant enzymes, such as catalase, superoxide dismutases (SOD), MnSOD and Cu/ZnSOD, protect cells by scavenging reactive oxygen species (ROS). Numerous studies have reported the anti-cancer effects of 1,25-dihydroxyvitamin D3 (calcitriol) and its related analogues, seocalcitol and analogue V. In this study, canine bladder transitional cell carcinoma (cbTCC) cells were used to determine effects of calcitriol and its related analogues on antioxidant enzyme gene expression, protein expression and activity. Catalase mRNA was increased in response to calcitriol (10(-7) M), and seocalcitol (10(-7) and 10(-9) M). MnSOD mRNA was decreased in response to calcitriol at 10(-7) M. Catalase was significantly increased in response to calcitriol (10(-7) and 10(-9) M), and seocalcitol (10(-9) M). Catalase enzymatic activity increased in response to calcitriol, seocalcitol and analogue V (10(-9) M). In addition, global gene expression analysis identified the involvement of mitogen-activated protein kinase (MAPK) signalling in cbTCC's response to calcitriol and seocalcitol treatment.

Heterogeneity in Intratumor Correlations of 18F-FDG, 18F-FLT, and 61Cu-ATSM PET in Canine Sinonasal Tumors

Intratumor heterogeneity in biologic properties and in relationships between various phenotypes may present a challenge for biologically targeted therapies. Understanding the relationships between different phenotypes in individual tumor types could help inform treatment selection. The goal of this study was to characterize spatial correlations of glucose metabolism, proliferation, and hypoxia in 2 histologic types of tumors. Twenty canine veterinary patients with spontaneously occurring sinonasal tumors (13 carcinomas and 7 sarcomas) were imaged with (18)F-FDG, (18)F-labeled 3'-deoxy-3'-fluorothymidine ((18)F-FLT), and (61)Cu-labeled diacetyl-bis(N(4)-methylthiosemicarbazone) ((61)Cu-ATSM) PET/CT on 3 consecutive days. Precise positioning and immobilization techniques coupled with anesthesia enabled motionless scans with repeatable positioning. Standardized uptake values (SUVs) of gross sarcoma and carcinoma volumes were compared by use of Mann-Whitney U tests. Patient images were rigidly registered together, and intratumor tracer uptake distributions were compared. Voxel-based Spearman correlation coefficients were used to quantify intertracer correlations, and the correlation coefficients of sarcomas and carcinomas were compared. The relative overlap of the highest uptake volumes of the 3 tracers was quantified, and the values were compared for sarcomas and carcinomas. Large degrees of heterogeneity in SUV measures and phenotype correlations were observed. Carcinoma and sarcoma tumors differed significantly in SUV measures, with carcinoma tumors having significantly higher (18)F-FDG maximum SUVs than sarcoma tumors (11.1 vs. 5.0; P = 0.01) as well as higher (61)Cu-ATSM mean SUVs (2.6 vs. 1.2; P = 0.02). Carcinomas had significantly higher population-averaged Spearman correlation coefficients than sarcomas in comparisons of (18)F-FDG and (18)F-FLT (0.80 vs. 0.61; P = 0.02), (18)F-FLT and (61)Cu-ATSM (0.83 vs. 0.38; P < 0.0001), and (18)F-FDG and (61)Cu-ATSM (0.82 vs. 0.69; P = 0.04). Additionally, the highest uptake volumes of the 3 tracers had significantly greater overlap in carcinomas than in sarcomas. The relationships of glucose metabolism, proliferation, and hypoxia were heterogeneous across different tumors, with carcinomas tending to have high correlations and sarcomas having low correlations. Consequently, canine carcinoma tumors are robust targets for therapies that target a single biologic property, whereas sarcoma tumors may not be well suited for such therapies. Histology-specific PET correlations have far-reaching implications for the robustness of biologic target definition.

Clinical, cytologic, and histologic features of a mammary micropapillary carcinoma in a dog

Mammary invasive micropapillary carcinoma is a rare variant of mammary carcinoma that was recently recognized in dogs. The cytologic features and biologic behavior of such neoplasms in dogs have not yet been widely discussed in the veterinary literature. We report the clinical, cytologic, and histologic features of a canine micropapillary carcinoma in a 13-year-old female mongrel dog. The mammary region presented with extreme local pain, severe edema and erythema, and multifocal epidermal ulceration, which is typical for an inflammatory mammary carcinoma. Fine-needle aspirates were highly cellular and consisted of individual cells and papillary cell clusters with characteristics of malignant epithelial cells. Histologic examination revealed neoplastic cells arranged in small papillae without fibrovascular cores, sometimes inside clear lymphatic spaces, indicating lymphovascular invasion. Regional lymph node evaluation revealed metastatic cells. Due to deteriorating clinical condition the dog was euthanatized 5 months after mastectomy. At necropsy, metastatic neoplastic mammary cells were found in popliteal and mediastinal lymph nodes, the right femoral biceps muscle, liver, heart, lungs, and urinary bladder.

Canine carcinomas in benign mixed tumours: versican expression and association with invasion

Background Components of the extracellular matrix have been studied in the attempt to elucidate the mechanisms involved with biological behavior of tumours. The presence of the proteoglycan versican has been strongly associated to cancer development and progression, however its relationship with invasion and tumoral progression has been little studied in veterinary medicine. Carcinomas in benign mixed tumours (CBMT) are one of the most common malignant tumour in female dogs and can serve as a model for studies on tumour progression. The aim of this paper was to evaluate the expression of versican in in situ and invasive carcinomatous areas of CBMT.

Breed predisposition to canine gastric carcinoma - a study based on the Norwegian canine cancer register

BackgroundPrevious research has indicated a breed predisposition to gastric carcinoma in dogs. However, results to date are inconsistent since several studies have failed to prove such a predisposition. Better knowledge of breeds at risk could facilitate early detection of gastric carcinoma in dogs. The aim of the study was to retrospectively investigate the proportion and possible breed predisposition to canine gastric carcinoma using the Norwegian Canine Cancer Register for calculations of proportional morbidity ratios (PMRs) for the period 1998–2009.ResultsHistologically verified tumours recorded in the Norwegian Canine Cancer Register were studied (n = 19,715). A total of 31 (0.16%) cases of canine gastric carcinomas were identified. The median age of affected dogs was 10 years. The most commonly reported clinical signs were vomiting, anorexia, and weight loss. Males had significantly higher odds of gastric carcinoma than females (P = 0.02). The PMR with 95% confidence interval (CI) was calculated for each breed, and a breed predisposition was identified. Individuals of the breeds Tervuren (PMR 56.1), Bouvier des Flandres (PMR 36.5), Groenendael (PMR 34.5), Collie (PMR 26.1), Standard poodle (PMR 7.6), and Norwegian elkhound (PMR 6.1) had a significantly increased risk of developing gastric carcinoma.Discussion and conclusionThe proportion of cases of gastric carcinoma recorded in the Norwegian Canine Cancer Register was found to be 0.16%, and a breed predisposition was identified. The breed predisposition observed in the current study indicates a genetic susceptibility to gastric carcinoma.

Beta-catenin expression in pilomatrix carcinoma with multiple visceral metastases in a dog

Beta-catenin is a protein initially identified as a submembrane component of the E-cadherin-mediated cell-to-cell adhesion system. It plays a role as a transcriptional factor in the wingless/Wnt signalling pathway. Beta-catenin has been associated with oncogenic activity in human benign and malignant pilomatrix neoplasms where the immunohistochemical profile of β-catenin expression displayed both nuclear and cytoplasmic staining in basaloid cells. In this study, an 8-year-old female Irish setter dog was examined because of the presence of skin nodules. Tissue biopsies from different nodules were obtained and histological examination suggested a diagnosis of pilomatrix carcinoma. The dog spontaneously died after 2 months and necropsy showed multiple metastases in the nasal cavity, lungs, heart, kidney, liver and colon. Routine histopathology of metastatic sites showed features consistent with the pattern of primary neoplastic nodules. Immunohistochemical detection of β-catenin was performed in both the primary tumour and the metastases. Beta-catenin expression was located in the nuclei, cytoplasm and membrane of squamoid cells and in the cytoplasm of basaloid cells, while shadow cells were completely negative. To the best of our knowledge, these data represent the first report on the immunohistochemical expression profile of β-catenin in canine pilomatrix carcinoma.

Versican expression in canine carcinomas in benign mixed tumours: is there an association with clinical pathological factors, invasion and overall survival?

BackgroundComponents of the extracellular matrix have been studied in an attempt to elucidate the mechanisms involved in the biological behaviour of tumours. The presence of the proteoglycan versican has been strongly associated with cancer development and progression. However, relationship between versican expression and clinical pathological factors and overall survival has not been previously studied in veterinary medicine. Carcinomas in benign mixed tumours (CBMTs) are one of the most common malignant tumours in female canines and can serve as models for studies of tumour progression. The aim of this study was to evaluate the expression of versican in in situ and invasive carcinomatous areas of canine CBMTs and to evaluate possible associations of versican expression with other classic prognostic factors and overall survival.ResultsClinical staging; histological grade determination; immunohistochemical staining for versican, E-cadherin and Ki-67; and confirmation of invasion areas by staining for p63 and smooth muscle α-actin (α-SMA) were performed on 49 canine cases of CBMT. Tumour invasion was considered when suspicious Haematoxylin-Eosin (HE)-stained areas showed a total loss of α-SMA and p63 immunoreactivity. Versican immunoreactivity was less intense in the areas adjacent to the in situ carcinomatous regions, compared to invasive regions, which showed extensive and strong staining.ConclusionsOur data reveal that in canine CBMTs, versican expression differs significantly between invasive and in situ areas, suggesting a role for this molecule in tumour progression. Although a direct relationship exists between versican and invasiveness, our results indicate that the isolated evaluation of this proteoglycan does not represent an independent prognostic factor in canine CBMTs.

64Cu-ATSM and 18FDG PET uptake and 64Cu-ATSM autoradiography in spontaneous canine tumors: comparison with pimonidazole hypoxia immunohistochemistry

BackgroundThe aim of this study was to compare 64Cu-diacetyl-bis(N4-methylsemicarbazone) (64Cu-ATSM) and 18FDG PET uptake characteristics and 64Cu-ATSM autoradiography to pimonidazole immunohistochemistry in spontaneous canine sarcomas and carcinomas.MethodsBiopsies were collected from individual tumors between approximately 3 and 25 hours after the intravenous injection of 64Cu-ATSM and pimonidazole. 64Cu-ATSM autoradiography and pimonidazole immunostaining was performed on sectioned biopsies. Acquired 64Cu-ATSM autoradiography and pimonidazole images were rescaled, aligned and their distribution patterns compared. 64Cu-ATSM and 18FDG PET/CT scans were performed in a concurrent study and uptake characteristics were obtained for tumors where available.ResultsMaximum pimonidazole pixel value and mean pimonidazole labeled fraction was found to be strongly correlated to 18FDG PET uptake levels, whereas more varying results were obtained for the comparison to 64Cu-ATSM. In the case of the latter, uptake at scans performed 3 h post injection (pi) generally showed strong positive correlated to pimonidazole uptake.Comparison of distribution patterns of pimonidazole immunohistochemistry and 64Cu-ATSM autoradiography yielded varying results. Significant positive correlations were mainly found in sections displaying a heterogeneous distribution of tracers.ConclusionsTumors with high levels of pimonidazole staining generally displayed high uptake of 18FDG and 64Cu-ATSM (3 h pi.). Similar regional distribution of 64Cu-ATSM and pimonidazole was observed in most heterogeneous tumor regions. However, tumor and hypoxia level dependent differences may exist with regard to the hypoxia specificity of 64Cu-ATSM in canine tumors.