Galectin-3 immunolabelling correlates with BCL2 expression in canine cutaneous mast cell tumours.

Mast cell tumour (MCT) is the most frequent skin neoplasm in dogs. These tumours are characterised by variable behaviour and clinical presentation that make prognosis an important and challenging task in the veterinary practice. Galectin-3 (Gal-3) is known to influence several biological processes that are important in the cancer context and has been described as a prognostic marker for several human cancers. The aim of the present work was to characterise Gal-3 immunolabelling in canine cutaneous MCTs and to investigate its value as a prognostic marker for the disease. Thirty-four random cases of canine cutaneous MCT that were surgically treated with wide margins were included in this study. Gal-3 expression was evaluated using immunohistochemistry and the results were compared with the expression of apoptosis-related proteins, Ki67 index, histopathological grades, mortality due to the disease and post-surgical survival. The majority of the MCTs (65.8%) were positive for Gal-3. Gal-3 immunolabelling was variable among the samples (2.7%-86.8% of the neoplastic cells). The protein was located in the cytoplasm or in the cytoplasm and the nucleus. Gal-3 positivity was correlated with BCL2 expression (P < 0.001; r = 0.604), but not with Ki67 and BAX. No significant differences were detected between histological grades or in the survival analysis. Gal-3 expression correlates with BCL2 expression in MCTs. Although an efficient marker for several human neoplasms, the results presented herein suggest that Gal-3 immunolabelling is not an independent prognostic indicator for this disease.

Intratumoral collagen index predicts mortality and survival in canine cutaneous mast cell tumours.

BACKGROUND: Mast cell tumours (MCTs) constitute almost 25% of cutaneous neoplasms in dogs. Their biological behaviour is predicted using histopathological grading which is based on several subjective criteria that are vulnerable to intra- and interobserver variability. To improve the prediction of the biological behaviour, several complementary markers have been studied. The integrity of the extracellular matrix (ECM) may play a protective role against tumoral progression, and favour cellular proliferation, angiogenesis, invasion and metastases when altered. HYPOTHESIS/OBJECTIVES: To evaluate the quantification of collagen and elastic fibres as prognostic markers for MCTs. ANIMALS: Thirty-eight random cases of canine cutaneous MCT surgically treated with wide margins were included. METHODS AND MATERIALS: Intratumoral collagen and elastic fibres were identified and quantified on histological sections stained with Masson's trichrome, Picrosirius red and Verhoeff; the results were compared with histopathological grades, mortality due to the disease and postsurgical survival. RESULTS: Morphometric analysis revealed a significant relationship between histopathological grade and intratumoral collagen index (CoI). In addition, the CoI was considered an independent indicator for mortality and postsurgical survival. CONCLUSIONS AND CLINICAL IMPORTANCE: These results support the importance of the CoI in the grading and prognosis of MCTs, suggesting that preservation and/or synthesis of collagen have the potential to become targets for MCT therapeutics.

Nanog Expression and Proliferation Indices in Canine Cutaneous Mast Cell Tumors.

Mast cell tumors are one of the most frequent skin tumors in dogs. Treatment decisions often depend on a wide range of clinical information and the main criteria for prognostic formulation are histological grade, mitotic count, Ki67 index, and KIT immunostaining pattern. NANOG is a pluripotency factor expressed by normal and cancer stem cells, which is a prognostic marker and a potential therapeutic target for several human tumors. In the present study, mast cell tumor samples from 41 dogs were evaluated for NANOG and Ki67 by immunohistochemistry. All samples were positive for NANOG but its expression was not correlated with Ki67 index and no significant differences were found with respect to histopathological grades, disease-related mortality, or survival. Our results suggest that, although related to pluripotency, NANOG expression does not correlate with proliferative activity, and is not a reliable prognostic factor for canine cutaneous mast cell tumors.

Liver transcriptomic networks reveal main biological processes associated with feed efficiency in beef cattle.

BACKGROUND: The selection of beef cattle for feed efficiency (FE) traits is very important not only for productive and economic efficiency but also for reduced environmental impact of livestock. Considering that FE is multifactorial and expensive to measure, the aim of this study was to identify biological functions and regulatory genes associated with this phenotype. RESULTS: Eight genes were differentially expressed between high and low feed efficient animals (HFE and LFE, respectively). Co-expression analyses identified 34 gene modules of which 4 were strongly associated with FE traits. They were mainly enriched for inflammatory response or inflammation-related terms. We also identified 463 differentially co-expressed genes which were functionally enriched for immune response and lipid metabolism. A total of 8 key regulators of gene expression profiles affecting FE were found. The LFE animals had higher feed intake and increased subcutaneous and visceral fat deposition. In addition, LFE animals showed higher levels of serum cholesterol and liver injury biomarker GGT. Histopathology of the liver showed higher percentage of periportal inflammation with mononuclear infiltrate. CONCLUSION: Liver transcriptomic network analysis coupled with other results demonstrated that LFE animals present altered lipid metabolism and increased hepatic periportal lesions associated with an inflammatory response composed mainly by mononuclear cells. We are now focusing to identify the causes of increased liver lesions in LFE animals.

Intercellular interactions between mast cells and stromal fibroblasts obtained from canine cutaneous mast cell tumours.

Mast cell tumours (MCTs) are the most frequent malignant skin neoplasm in dogs. Due to the difficulty in purifying large numbers of canine neoplastic mast cells, relatively little is known about their properties. A reproducible in vitro model is needed to increase the understanding about the phenotype and functional properties of neoplastic mast cells. In the present study, we describe the establishment of primary cocultures of neoplastic mast cells from canine cutaneous MCTs and cancer-associated fibroblasts. We confirmed the inability of canine neoplastic mast cells to remain viable for long periods in vitro without the addition of growth factors or in vivo passages in mice. Using a transwell system, we observed that mast cell viability was significantly higher when there is cell-to-cell contact in comparison to non-physical contact conditions and that mast cell viability was significantly higher in high-grade than in low-grade derived primary cultures. Moreover, the use of conditioned medium from co-cultured cells led to a significantly higher tumoral mast cell viability when in monoculture. Signalling mechanisms involved in these interactions might be attractive therapeutic targets to block canine MCT progression and deserve more in-depth investigations.

Identification of two molecular subtypes in canine mast cell tumours through gene expression profiling.

Mast cell tumours (MCTs) are common neoplasms in dogs and are usually regarded as potentially malignant. Several studies have attempted to identify biomarkers to better predict biological behaviours for this tumour. The aim of this study was to identify pathways connected to clinical and histopathological malignancies, shorter survival times, and poor prognoses associated with MCTs. We performed genome-wide gene expression analyses on tissues obtained from 15 dogs with single MCTs, and identified two distinct tumour subtypes-high-risk and low-risk-associated with differences in histological grades, survival times, Ki67 indices, and occurrence of death due the disease. Comparative analyses of RNA sequence profiles revealed 71 genes that were differentially expressed between high- and low-risk MCTs. In addition to these analyses, we also examined gene co-expression networks to explore the biological functions of the identified genes. The network construction revealed 63 gene modules, of which 4 were significantly associated with the more aggressive tumour group. Two of the gene modules positively correlated with high-risk MCTs were also associated with cell proliferation and extracellular matrix-related terms. At the top of the extracellular matrix module category, genes with functions directly related to those of cancer-associated fibroblasts (CAFs) were identified. Immunohistochemical analyses also revealed a greater number of CAFs in high-risk MCTs. This study provides a method for the molecular characterisation of canine MCTs into two distinct subtypes. Our data indicate that proliferation pathways are significantly involved in malignant tumour behaviours, which are known to be relevant for the induction and maintenance of MCTs. Finally, animals presenting high-risk MCTs overexpress genes associated with the extracellular matrix that can be robustly linked to CAF functions. We suggest that CAFs in the MCT stroma contribute to cancer progression.

Immunohistochemical expression of Galectin-3 in canine tumors

Galectin-3 (Gal-3) is a protein expressed by both normal and neoplastic cells. It participates in several biological processes such as cell proliferation, cell adhesion, apoptosis, tissue remodeling, and angiogenesis. Although it is known to serve as a valuable prognostic marker in several types of human cancer, there are few reports about its applicability as a marker in the veterinary oncology literature. The aim of the present study was to characterize Gal-3 expression in different types of canine tumors. Fifty-three tissue samples from 22 histologically different types of canine tumors were immunohistochemically evaluated for Gal-3 expression. Variations in the percentage of Gal-3-positive cells, localization of Gal-3 protein, and percentage of Gal-3-positive fibroblasts were observed. These preliminary results showed variable expression of Gal-3 among canine tumors. Further studies are needed in order to investigate the potential of this protein as a prognostic marker and a therapeutic target.

Immunohistochemical expression of Galectin-3 in canine tumors

Galectin-3 (Gal-3) is a protein expressed by both normal and neoplastic cells. It participates in several biological processes such as cell proliferation, cell adhesion, apoptosis, tissue remodeling, and angiogenesis. Although it is known to serve as a valuable prognostic marker in several types of human cancer, there are few reports about its applicability as a marker in the veterinary oncology literature. The aim of the present study was to characterize Gal-3 expression in different types of canine tumors. Fifty-three tissue samples from 22 histologically different types of canine tumors were immunohistochemically evaluated for Gal-3 expression. Variations in the percentage of Gal-3-positive cells, localization of Gal-3 protein, and percentage of Gal-3-positive fibroblasts were observed. These preliminary results showed variable expression of Gal-3 among canine tumors. Further studies are needed in order to investigate the potential of this protein as a prognostic marker and a therapeutic target.(AU)

Matrix metalloproteinase 9 expression in canine mammary carcinomas

Mammary neoplasms are among the most common canine tumors, with high risk of invasion and metastasis. Important steps for these events are the loss of cell adhesion to the main tumor mass and extracellular matrix degradation. Matrix metalloproteinases (MMPs) are proteolytic enzymes containing zinc, which are capable of degrading and remodeling the surrounding extracellular matrix, facilitating these events. Involvement of MMPs has been demonstrated in many pathological processes, as well as in human and canine tumors, which has been related to malignancy and prognosis. The aim of this study was to characterize the immunohistochemical expression of matrix metalloproteinase 9 (MMP-9) in canine mammary gland tumors, as well as to verify its relation with the different histologic patterns. Thirty-one of the 41 tumors (75.61%) were positive. Twenty-two samples (70.97%) had diffuse cytoplasmic immunostaining and 9 (29.03%) had a finely granular pattern. Immunostaining intensity was strong in 21 (67.74%) tumors and weak in 10 (32.26%). No statistically significant differences were found between anaplastic carcinomas, carcinomas in a mixed tumor and simple carcinomas regarding positivity (p=0.9707), intensity (p=0.5386) and staining pattern (0.6135); between solid carcinomas and simple papillary carcinomas for positivity (p=0,7333), intensity (p=0.7333) and staining pattern (p=0.3037); or betweensolid carcinomas and simple tubular and papillary carcinomas for positivity (p=0.9682), intensity (p=0.8450) and staining pattern (p=0.5068). MMP-9 was detected with variable intensity and morphological patterns of cytoplasmic staining. However significant statistic differences were not found between the histological types or histopathological grades.(AU)

Matrix metalloproteinase 9 expression in canine mammary carcinomas

Mammary neoplasms are among the most common canine tumors, with high risk of invasion and metastasis. Important steps for these events are the loss of cell adhesion to the main tumor mass and extracellular matrix degradation. Matrix metalloproteinases (MMPs) are proteolytic enzymes containing zinc, which are capable of degrading and remodeling the surrounding extracellular matrix, facilitating these events. Involvement of MMPs has been demonstrated in many pathological processes, as well as in human and canine tumors, which has been related to malignancy and prognosis. The aim of this study was to characterize the immunohistochemical expression of matrix metalloproteinase 9 (MMP-9) in canine mammary gland tumors, as well as to verify its relation with the different histologic patterns. Thirty-one of the 41 tumors (75.61%) were positive. Twenty-two samples (70.97%) had diffuse cytoplasmic immunostaining and 9 (29.03%) had a finely granular pattern. Immunostaining intensity was strong in 21 (67.74%) tumors and weak in 10 (32.26%). No statistically significant differences were found between anaplastic carcinomas, carcinomas in a mixed tumor and simple carcinomas regarding positivity (p=0.9707), intensity (p=0.5386) and staining pattern (0.6135); between solid carcinomas and simple papillary carcinomas for positivity (p=0,7333), intensity (p=0.7333) and staining pattern (p=0.3037); or betweensolid carcinomas and simple tubular and papillary carcinomas for positivity (p=0.9682), intensity (p=0.8450) and staining pattern (p=0.5068). MMP-9 was detected with variable intensity and morphological patterns of cytoplasmic staining. However significant statistic differences were not found between the histological types or histopathological grades.