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Obesity may be associated with the onset of mammary tumors in women. In companion animals, these data are still scarce, mainly associating the clinic of the patient with laboratory and histological findings. This study aimed to evaluate the clinical and laboratory aspects of female dogs with mammary neoplasia, investigating whether they are related to obesity. Four groups of spayed or non-spayed female dogs were studied, divided into (G1) female dogs without mammary tumor and normal body condition score (BCS), (G2) female dogs without mammary tumor and obese, (G3) female dogs with mammary tumor and normal BCS and (G4) female dogs with mammary tumor and obese. BCS, canine body mass index (CBMI), blood count, glucose, total cholesterol, triglycerides and cytopathological and histopathological examinations were evaluated. Mixed-breed animals were the most prevalent in this study (67.5%). There was a limitation regarding the use of CBMI related to body proportionality. Considering the 28 tumors evaluated, carcinoma in mixed tumor was the most prevalent malignant histological type, while adenomyoepithelioma was the most prevalent benign histological type. It was possible to conclude that obesity was not related to clinical and laboratory changes in the female dogs affected with mammary neoplasias. In addition, no relationship was noted between BCS and CBMI with the histological type or malignancy of mammary neoplasia, since the malignant histological types were the most prevalent tumors in both the ideal score group and the overweight to obese group. RESUMO: A obesidade pode estar associada ao aparecimento de tumores mamários em mulheres. Em animais de companhia, esse dado ainda é escasso, principalmente associando a clínica da paciente aos achados laboratoriais e histológicos. Este estudo objetivou avaliar os aspectos clínicos e laboratoriais de cadelas com neoplasia mamária, investigando se estão relacionadas à obesidade. Foram estudados quatro grupos de cadelas castradas ou não castradas, divididas em (G1) cadelas sem tumor de mama e Escore de Condição Corporal normal (BCS), (G2) cadelas sem tumor de mama e obesa, (G3) cadelas com tumor de mama e ECC normal e (G4) cadelas com tumor de mama e obesa. Foram avaliados o Escore de Condição Corporal (ECC), Índice de Massa Corporal Canina (IMC), hemograma, glicose, colesterol total, triglicerídeos e exames citopatológicos e histopatológicos. Os animais de raça mista foram os mais prevalentes neste estudo (67,5%). Houve uma limitação quanto ao uso do IMC relacionado à proporcionalidade corporal. Considerando os 28 tumores avaliados, o carcinoma em tumor misto foi o tipo histológico maligno mais prevalente, enquanto o adenomioepitelioma foi o tipo histológico benigno mais prevalente. Foi possível concluir que a obesidade não esteve relacionada a alterações clínicas e laboratoriais nas cadelas acometidas por neoplasias mamárias. Além disso, não foi observada relação entre BCS e CBMI com o tipo histológico ou malignidade das neoplasias mamárias, uma vez que os tipos histológicos malignos foram os tumores mais prevalentes no grupo escore ideal e no grupo com sobrepeso e obesidade.

Mammary tumors in female dogs are the most frequent and corresponds to half of the canine tumors. The objectives of this study were to determine the risk factors associated with the occurrence of mammary tumors in female dogs and to evaluate the macroscopic characteristics of these neoformations, using 386 dogs from the “Outubro Rosa Pets” events done within the cities of Uberlândia and Patos de Minas, Minas Gerais State, Brazil, in 2015 (n=194), 2016 (n=105) and 2017 (n=87). For the determination of risk factors, the binary logistic regression test (P5cm). At least 15.4% (14/91) of the dogs had one of the regional lymph nodes increased. In conclusion, the occurrence of mammary tumors in the evaluated population was 23.6% and that age, overweight and non-realization of ovariohysterectomy are risk factors associated with the development of mammary tumors.

A defective homologous recombination (HR) repair program increases tumor incidence as well as providing a survival advantage in patients with breast and ovarian cancers. Here, we hypothesize that the tumor-promoting side of genome maintenance programs may be contributed by a self-renewal protein, nucleostemin (NS). To address this issue, we established its functional importance in mammary tumor progression in mice and showed that mammary tumor cells become highly susceptible to replicative DNA damage following NS depletion and are protected from hydroxyurea-induced damage by NS overexpression. Breast cancer cells with basal-like characters display more reliance on NS for genome maintenance than those with luminal characters. Mechanistically, NS-deficient cells demonstrate a significantly reduced HR repair activity. TCGA analyses of human breast cancers revealed that NS is co-enriched positively with HR repair proteins and that high NS expression correlates with low HR defects and predicts poor progression-free survival and resistance to knockdown of cell cycle checkpoint genes in triple-negative/basal-like breast cancers. This work indicates that NS constitutes a tumor-promoting genome maintenance program required for mammary tumor progression.

Simple Summary Shear wave elastography (SWE) is a new diagnostic method allowing for a non-invasive differential diagnosis between benign and malignant mammary tumors. Mammary tumors in dogs are often hormone-dependent, and a surgical approach is currently the most recommended method for the treatment of mammary neoplasia. However, preoperative, pharmacological therapy eliminating hormonal stimulation can sometimes be indicated to reduce the size of the tumor and facilitate subsequent surgery. The aim of this study was to evaluate the influence of the reduction in the benign tumor size observed after treatment with the use of aglepristone on the shear wave elastography results, obtained before and after therapy. We noticed that a fast and significant reduction in tumor size, as a consequence of preoperative pharmacological treatment, did not influence the diagnosis performed using the SWE technique. These results seem to indicate the accuracy and usefulness of this new diagnostic method, and confirm the hypothesis that tumor tissue density is a valuable parameter when determining the benignancy of mammary tumors in dogs. Abstract Shear wave elastography (SWE) can be useful to discriminate between malignant and benign mammary tumors. In dogs with elevated progesterone levels compared to the baseline and fast-growing tumors, treatment with the use of aglepristone allows for tumor size reduction, which facilitates surgery. This study aimed to evaluate the influence of the preoperative treatment of benign mammary tumors (BMTs), performed with the use of aglepristone, on the density of the tumor tissue measured by SWE. Twelve female dogs with diagnosed BMTs and increased levels of progesterone were treated with aglepristone (Alizine, Virbac, France) at 10 mg/kg s.c. (Subcutaneous injection). twice, with a 24 h interval. The density of the tumor was evaluated by SWE before and after the treatment. The type of tumor was evaluated by fine needle aspiration cytology before treatment, and a histopathological examination was made after surgical removal, performed after the aglepristone treatment. In all the cases, a significant reduction in the mammary tumor’s size was observed following treatment, with no influence on the density of the tumor’s tissue measured by SWE. Similar studies on malignant mammary tumors are warranted to verify if in these cases, density will also be a constant parameter that is not dependent on the tumor size.

Background: Breast cancer is the most common cancer in women worldwide and is the leading cause of death amongst women with cancer. One novel therapy used for breast cancer treatment constitutes non-contact electric fields and is called electro-capacitive cancer therapy (ECCT) with intermediate frequency and low intensity. The objective of this study was to examine the effect of ECCT on mammary tumors growth in rats and observing the immune responses that play a role in fighting the tumor. Methods: Female SD rats were used and divided into four groups, namely control (NINT), placebo (NIT), non- therapy (INT), and therapy (IT) groups with 6 biological replicates in each group. Rats in INT and IT groups were treated with 7,12-dimethylbenz[a]anthracene for mammary tumor induction. Only rats in NIT and IT groups were exposed to ECCT individually for 10 hours per day for 21 days. The size of all tumors was measured with a digital caliper. The distributions of PCNA, ErbB2, caspase-3, CD68, CD4, and CD8-positive cells were observed with immunohistochemistry and scoring with ImageJ. Results: The growth rate of mammary tumors in IT group was significantly lower (p Conclusions: Non-contact electric fields exposure showed inhibition on mammary tumor growth in rats while inducing CD8+ T cells, leading to tumor cell death and potentially helping wounds heal.

As neoplasias mamárias em cadelas são afecções de significativa importância em medicina veterinária pela sua alta frequência, além de serem modelo para o estudo do câncer de mama na mulher. Nesse sentido, se faz necessária a realização de estudos continuados acerca da frequência de tumores e suas características clinicopatológicas. Constituem ainda um grupo heterogêneo de tumores quanto aos padrões histológicos e comportamento biológico, o que torna mais complexo e urgente a identificação de fatores de prognóstico e que possibilitem diagnosticar e tratar de forma mais eficaz animais portadores de tumor de mama. Nos últimos anos, tem se intensificado estudos dirigidos à identificação de marcadores moleculares envolvidos nos inúmeros eventos celulares que ocorrem durante a carcinogênese, como crescimento e diferenciação celular, proliferação, invasão e metástase. O receptor do fator de crescimento epidérmico humano tipo 2 (HER-2) é uma glicoproteína de membrana da família tirosina-quinase, codificada por um gene de mesmo nome, diretamente relacionada a mudanças significativas na proliferação celular e sobrevivência das células tumorais. Durante o processo de mutação desse gene ocorre hiperativação da cascata de sinalização intracelular, que resulta em rápido crescimento das células tumorais. Na mulher, a superexpressão de HER-2 está associada a neoplasias mamárias cujos parâmetros morfológicos sugerem malignidade e pior prognóstico, resultando em alta taxa de recidiva e de mortalidade no estágio inicial da doença, além de elevada incidência de metástases. Entretanto, na cadela, estudos que investigaram o papel do HER-2 nas neoplasias mamárias, com emprego da imunohistoquímica, não são consensuais até então, mantendo obscuro o significado da sobrexpressão de HER-2 nestas neoplasias. Com intuito de auxiliar na determinação de fatores prognósticos fidedignos para os tumores mamários nas cadelas, o presente trabalho teve como objetivos: determinar a prevalência de lesões mamárias diagnosticadas em cadelas no Laboratório de Patologia Veterinária da Universidade Federal de Uberlândia entre 2004 e 2014, bem como a relação entre aspectos epidemiológicos (idade e raça) e clínicopatológicos (ulceração, tamanho do tumor e comportamento biológico) na ocorrência dos tumores de mama; e verificar a expressão de HER-2 em carcinomas mamários de cadelas e sua relação com o tipo e grau histológico, idade das cadelas, metástase em linfonodos e à distância, tamanho tumoral e estadiamento clínico. Mammary tumors in female dogs are important diseases in veterinary medicine due to their high frequency, besides being a model for the study of breast cancer in women. So, it is necessary to continuous studies on the frequency of tumors and their clinicopathological characteristics. They also constitute a heterogeneous group of tumors in correlation with histological patterns and biological behavior, which makes it more complex and urgent to identify prognostic factors and to make it possible to diagnose and treat animals with mammary tumors more effectively. In the last years, there have been intensified the number of studies about the identification of molecular markers involved in the innumerable cellular events that occur during carcinogenesis, such as cell growth and differentiation, proliferation, invasion and metastasis. HER-2 is a membrane glycoprotein of the tyrosine kinase family, encoded by a gene with the same name, directly related to significant changes in cell proliferation and survival of tumor cells. During mutation process of this gene, hyperactivation of intracellular signaling cascade results in a rapid growth of tumor cells. In women, HER-2 overexpression is associated with breast neoplasms whose morphological parameters suggest poor prognosis and malignancy, resulting in a high rate of recurrence and mortality in the early stage of the disease, as well as a high incidence of metastases. However, in the female dog, until now the extensive variability of results obtained from immunohistochemical protocols proposed for molecular classification, keeps the meaning of HER-2 overexpression in these neoplasms obscure. In order to assist determination of the reliable prognostic factors for canine breast neoplasms, the present study: determined the prevalence of breast lesions diagnosed in female dogs in Laboratory of Veterinary Pathology of the Federal University of Uberlândia between 2004 and 2014, as well as the correlation between epidemiological aspects (age and breed) and clinicopathological (ulceration, tumor size and biological behavior) in the occurrence of breast tumors; verified the HER-2 expression in female mammary carcinomas of dogs and their relationship with the type and histological grade, age of patient, metastasis in lymph nodes or distants, tumor size and clinical staging. Tese (Doutorado)

Mammary tumor is the most frequent among the tumors that affect canine females, with relevant importance in veterinary medicine. The objective of this study was to determine the image characteristics of mammary tumors in female dogs, and compare different ultrasonographic techniques for neoplastic evaluation. During the experiment, 30 bitches with presence of nodular lesion in the mammary gland were used. Initially females were submitted to clinical and laboratory evaluations, and subsequent to the ultrasound examination of the tumor mass, as well as abdominal ultrasound and thoracic x-ray for the metastasis investigation. Quantitative analysis by histogram of the gray levels and categorization of the tumor masses by the BI-RADS system were performed. Later, the bitches were submitted to surgical resection of the tumors, where samples of the neoplastic tissue were collected for histopathological analysis. Carcinoma in mixed tumor showed a higher rate (33.3%), and the malignancy degree of epidermal tumors were classified in grade 1 (n=9), grade 2 (n=12) and grade 3 (n=3). Malignancy degree showed positive correlation with BI-RADS (r=0.55; P

Simple Summary Canine malignant mammary tumor (MMT) is a prevalent malignancy in intact female dogs. A current lack of easily accessible tumor biomarkers hinders a timely assessment of the disease outcome. This study reveals that anterior gradient protein 2 (AGR2) is overexpressed in canine MMT tissues, and elevated levels of extracellular AGR2 in sera of MMT dogs are significantly associated with progression and remote metastasis of MMT and an unfavorable overall survival of the patients. Hence, serum eAGR2 level is significantly associated with an adverse outcome of MMT dogs and holds a predictive potential in MMT prognosis. Abstract Canine malignant mammary tumors (MMTs) are prevalent malignancy in intact female dogs with a high incidence of metastasis and recurrence. A current lack of easily accessible tumor biomarkers hinders a timely assessment of the disease outcome. We previously identified anterior gradient protein 2 (AGR2) with higher protein abundance in canine MMT tissues compared with normal counterparts. AGR2 is an endoplasmic reticulum-resident protein disulfide isomerase involved in the regulation of protein processing and also exists extracellularly via secretion to exert pro-oncogenic functions. In the present study, we validated overexpression of AGR2 in canine MMT tissues from 45 dogs using immunohistochemistry and immunoblotting, and assessed serum AGR2 levels in 81 dogs with MMTs and 21 benign cases using a competitive enzyme-linked immunosorbent assay (ELISA). Our data revealed that serum eAGR2 levels are significantly correlated with MMT progression (p = 0.0007) and remote tumor metastasis (p = 0.002). Moreover, elevated levels of serum eAGR2 are associated with an unfavorable overall survival of MMT dogs in later stage (p = 0.0158). Area under the time-dependent ROC curve (AUC) of serum eAGR2 level as a prognostic indicator was 0.839. Collectively, this study uncovered that serum eAGR2 level is significantly associated with an adverse outcome of MMT dogs and holds a predictive potential in MMT prognosis.

We determined cytologic features of histologically confirmed subcentimeter canine mammary tumors (CMTs) to determine reasonable criteria for an accurate cytologic diagnosis. Fifty-three CMTs from 28 bitches were included. All cytologic samples were collected by ultrasound-guided fine-needle aspiration biopsy, stained with May-Grünwald/Giemsa, and retrospectively evaluated using a scoring system established for 18 cytologic features. Mean nuclear area (MNA) was also measured for each sample by a computer-assisted program. Based on the histologic diagnosis, CMTs were divided into 2 groups: malignant tumors (25) and benign lesions (15). Data were statistically analyzed using Fisher and Mann–Whitney tests. Chromatin pattern ( p < 0.05) and macrophage infiltration ( p < 0.05) were significantly different between the groups. Median MNA was significantly ( p < 0.05) larger in malignant tumors. The evaluation of these cytologic features in subcentimeter CMTs may increase the sensitivity of cytology.

// Robert Jones 1 , Katrina Watson 1 , Anthony Bruce 1 , Sarah Nersesian 1 , Jenna Kitz 1 , Roger Moorehead 1 1 Department of Biomedical Science, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada Correspondence to: Roger Moorehead, email: rmoorehe@uoguelph.ca Keywords: microRNA, miR-200f, miR-200c, mammary tumors, claudin-low Received: August 15, 2016 Accepted: February 06, 2017 Published: March 02, 2017 ABSTRACT Claudin-low breast cancer is a relatively rare breast cancer subtype. These cancers are typically ER - /PR - /HER2 - and express high levels of mesenchymal genes as well as genes associated with inflammation, angiogenesis and stem cell function. In addition to alterations in gene expression, it was recently demonstrated that claudin-low breast cancers express very low levels of the miR-200 family of miRNAs. Given that each miRNA can regulate tens, hundreds or even thousands of genes, miRNAs are being evaluated as therapeutic targets. In this study we show that mammary tumors from MTB-IGFIR transgenic mice and cell lines derived from these tumors represent a model of human claudin-low breast cancer and murine claudin-low mammary tumors and cell lines express only very low levels of all five members of the miR-200 family. Reduced miR-200 family expression appears to be regulated via methylation as cells and tumors expressing low levels of miR-200 family members had higher levels of CpG methylation in a putative promoter region than tumors and cells expressing high levels of miR-200 family members. Re-expression of miR-200c in murine claudin-low mammary tumor cells inhibited tumor cell proliferation and colony formation in vitro and tumor growth in vivo . With respect to tumor growth in vivo , re-expression of miR-200c was associated with a reduction in tumor vasculature and expression of Flt1 and Vegfc . Therefore, miR-200c is an important regulator of mesenchymal tumor cell growth.

Breast cancer is currently the leading cause of cancer death among women worldwide. AP-1 (c-Fos/c-Jun) isassociated with proliferation and survival, while cytoplasmic c-Fos activates phospholipid synthesis in cellsinduced to differentiate or grow. Estrogen receptor α 46 (ERα46) is a splice variant of full-length ERα66 and it isknown that it has an inhibitory role in cancer cell growth. We investigated c-Fos localization, its relationship toAP-1, the non genomic pathway of phospho-Tyr537-ERα66, as well as ERα46 and ERα66 isoforms in ratmammary gland development and carcinogenic transformation, and in mammary tumors. Female rats wereinjected: a) saline solution (Control mammary gland, CMG) or b) N-Nitroso-N-methyl urea (NMU), and sampleswere taken at 60, 90, 120 and 150 days of life. In addition, we analyzed hormone-dependent (HD) and in-dependent (HI) tumors in ovariectomized rats, and intact tumors (IT) in non-ovariectomized ones. Our resultsshow that, in CMG, nuclear c-Fos and proliferation decreased with age, AP-1 content was low, and nuclearERα46/ERα66 ratio was higher than 1. In NMU, nuclear c-Fos and proliferation increased with carcinogenictransformation, AP-1 content was high, and nuclear ERα46/ERα66 was below 1. As tumor grade increased,proliferation, nuclear c-Fos and AP-1 expression were negatively associated to nuclear ERα46/ERα66 in IT. InHD, nuclear ERα46/ERα66, nuclear c-Fos expression, AP-1 levels and proliferation were lower than in HI, whosegrowth is estrogen-independent. Phospho-Tyr537-ERα66 content and ERK1/2 activation were associated withAP-1 levels and cell proliferation. Collectively, our findings support the notion that variant detection andERα46/ERα66 ratio could shed light on the role of ERα isoforms in mammary gland transformation and thebehavior of ERα positive mammary tumors. Fil: Gutiérrez, Alicia Beatriz. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquímica Humana. Cátedra de Química Biologica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Sambuco, Lorena Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Físico Matemática; Argentina Fil: Alvarez, Laura. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquímica Humana. Cátedra de Química Biologica; Argentina Fil: Núñez, Mariel Alejandra. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Físico Matemática; Argentina Fil: Bergoc, Rosa Maria. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Físico Matemática; Argentina Fil: Zotta, Elsa. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Ciencias Fisiológicas. Laboratorio de Fisiopatogenia; Argentina Fil: Martín, Gabriela. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Físico Matemática; Argentina Fil: Randi, Andrea Silvana. Universidad de Buenos Aires. Facultad de Medicina. Departamento de Bioquímica Humana. Cátedra de Química Biologica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Although there are many studies about the cellular biomarkers’ use in canine’s mammary cancer, the results are not to compare. This paper offers orientations about the most useful immunohistochemical markers, which can help to treat canine’s mammal tumors. The main biomarkers of the canines’ mammal epithelia and of the myoepithelial cells were reviewed and based on that, some orientations about immunoexpression of cadherin (E cadherin and P cadherin), proliferation marker (Ki-67), Human Epidermal Growth Factor (HER2 and HER3), estrogen and progesterone receptors were made. The incorporation of these information in future studies, either they be prospective or retrospective, will offer mechanisms that allow the direct comparison of the studies, and therefore will help to determine if the biomarkers have prognostic significance. The use of these biomarkers can help to point out the most adequate treatment to malignant canine’s mammal cancers.

The mechanisms that drive ductal carcinoma in situ (DCIS) progression to invasive cancer are not clear. Studying DCIS progression in humans is challenging and not ethical, thus necessitating the characterization of an animal model that faithfully resembles human disease. We have characterized a canine model of spontaneous mammary DCIS and invasive cancer that shares histologic, molecular, and diagnostic imaging characteristics with DCIS and invasive cancer in women. The purpose of the study was to identify markers and altered signaling pathways that lead to invasive cancer and shed light on early molecular events in breast cancer progression and development. Transcriptomic studies along the continuum of cancer progression in the mammary gland from healthy, through atypical ductal hyperplasia (ADH), DCIS, and invasive carcinoma were performed using the canine model. Gene expression profiles of preinvasive DCIS lesions closely resemble those of invasive carcinoma. However, certain genes, such as SFRP2, FZD2, STK31, and LALBA, were over-expressed in DCIS compared to invasive cancer. The over-representation of myoepithelial markers, epithelial-mesenchymal transition (EMT), canonical Wnt signaling components, and other pathways induced by Wnt family members distinguishes DCIS from invasive. The information gained may help in stratifying DCIS as well as identify actionable targets for primary and tertiary prevention or targeted therapy.

Background As in women, regional lymph node status impacts survival in dogs with malignant mammary tumors. However, few studies have evaluated regional lymph node metastases in dogs with malignant mammary gland tumors. Objectives To estimate overall survival based on the assessments of the lymph node status and the morphologic and morphometric features in female dogs with malignant mammary gland tumors. Materials and Methods In total, 178 lymph nodes from 97 female dogs were assessed and reviewed, and after confirmation by immunohistochemistry (IHC), 161 lymph nodes were selected for analysis of metastases. Animals were considered metastasis-free (negative lymph nodes) only after IHC analysis for cytokeratin AE1/AE3. The number of positive lymph nodes, the number of metastatic foci, the maximum diameter and the area of metastasis were analyzed, and estimates of overall survival were made. Results Dogs with metastasis had lower mean survival than those with metastasis-free regional lymph nodes, showing a direct relationship between the number of affected lymph nodes and shorter survival. However, histologic analysis of the lymph nodes identified lower survival rates in animals with macrometastases and isolated tumor cells, areas of metastasis >20.11 mm², and metastatic diameters >7.32 mm. Conclusion The identification of ≥1 lymph nodes positive for metastasis and morphometric characterization of lymphatic metastases indicate the prognostic relevance of lymph nodes status in dogs with mammary tumors.

Histopathology is considered the gold standard diagnostic method for canine mammary tumors. In 2011, a new histologic classification for canine mammary tumors was proposed. The present study was a 2-year prospective study that validated the 2011 classification as an independent prognostic indicator with multivariate analysis in a population of 229 female dogs, identifying subtype-specific median survival times (MST) and local recurrence/distant metastasis rates. Dogs with benign tumors and carcinoma arising in benign mixed tumors all had an excellent prognosis. Dogs with complex carcinoma and simple tubular carcinoma also experienced prolonged survival. Those with simple tubulopapillary carcinoma, intraductal papillary carcinoma, and carcinoma and malignant myoepithelioma had a more than 10-fold higher risk of tumor-related death. The prognosis was even worse for adenosquamous carcinoma (MST = 18 months), comedocarcinoma (MST = 14 months), and solid carcinoma (MST = 8 months). The most unfavorable outcome was for anaplastic carcinoma (MST = 3 months) and carcinosarcoma (MST = 3 months), which also had the highest metastatic rates (89% and 100%, respectively). Adenosquamous carcinoma exhibited the highest local recurrence rate (50%). In the same canine population, the tumor diameter was recognized as a strong predictor of local recurrence/distant metastasis and an independent prognosticator of survival in the multivariate analysis. Excision margins were predictive only of local recurrence, whereas lymphatic invasion and histologic grade were predictive of local recurrence/distant metastasis and survival, although only in univariate analyses. In conclusion, this study validated the 2011 classification scheme and provided information to be used in the clinical setting and as the basis for future prognostic studies.

The PIM family of Ser/Thr kinase proteins has been implicated in tumorigenesis at different levels. PIM proteins are overexpressed in several tumor types and have been associated with chemoresistance. However, their role in hormone-dependent female tissues has not been explored, especially in the uterus, breast and ovary. We generated conditional transgenic mice with confined expression of human PIM1 or PIM2 genes in these tissues. We characterized the tumoral response to these genetic alterations corroborating their role as oncogenes since they induce hyperproliferation in all tissues and tumors in mammary gland and uterus. Furthermore, we observed a high degree of inflammatory infiltration in these tissues of transgenic mice accompanied by NFAT and mTOR activation and IL6 expression. Moreover, PIM1/2 were overexpressed in human breast, uterine and ovarian tumors, correlating with inflammatory features and stem cell markers. Our data suggest that PIM1/2 kinase overexpression provoke tissue alterations and a large IL6-dependent inflammatory response that may act synergistically during the process of tumorigenesis. The possible end-point is an increased percentage of cancer stem cells, which may be partly responsible for the therapy resistance found in tumors overexpressing PIM kinases., This work was funded by grants from the Spanish Ministry of Economy and Competitivity, Plan Estatal de I+D+I 2013–2016, ISCIII (Fis: PI15/00045) and CIBER de Cáncer (CD16/12/00275), co-funded by FEDER from Regional Development European Funds (European Union), Consejeria de Ciencia e Innovacion (CTS-1848) and Consejeria de Salud of the Junta de Andalucia (PI-0096-2014). Especial thanks to the AECC Foundation for also supporting this work. This work has also been made possible by the Fundacion BBVA. The Spanish Ministry of Education (FPU13/00426) funded MPJG.

To determine the associations between isoflavone (49.72% genistin, 5.32% daidzin, 34.54% glycitin) and breast cancer risk, 150 rats were given 5 mg 7,12-dimethylbenz(a)anthracene and half of them were ovariectomized. Then normal rats and ovariectomized rats were divided into 5 groups: control group, isoflavone high (HI), middle (MI), or low (LI) dose group consuming 100, 500, or 1000 mg isoflavones/kg diet, estrogen group (2.5 mg stilboestrol/kg diet). After 24 weeks, tumor incidences were 73% in control group, 7% in HI, 7% in MI, 27% in LI, and 80% in estrogen group for normal rats; 60% in control group, 13% in HI, 7% in MI, 13% in LI, and 73% in estrogen group for ovariectomized rats. Isoflavone treatment decreased tumor incidence and mean tumor number per rat and increased mean latent period compared with those in control group and estrogen group group significantly (p

In humans, the aryl hydrocarbon receptor (AHR) gene battery constitutes a set of contaminant-responsive genes, which have been recently shown to be involved in the regulation of several patho-physiological conditions, including tumorigenesis. As the domestic dog represents a valuable animal model in comparative oncology, mRNA levels of cytochromes P450 1A1, 1A2 and 1B1 (CYP1A1, 1A2 and 1B1), AHR, AHR nuclear translocator (ARNT), AHR repressor (AHRR, whose partial sequence was here obtained) and cyclooxygenase-2 (COX2) were measured in dog control tissues (liver, skin, mammary gland and bone), in 47 mast cell tumors (MCTs), 32 mammary tumors (MTs), 5 osteosarcoma (OSA) and related surgical margins. Target genes were constitutively expressed in the dog, confirming the available human data. Furthermore, their pattern of expression in tumor biopsies was comparable to that already described in a variety of human cancers; in particular, both AHR and COX2 genes were up-regulated and positively correlated, while CYP1A1 and CYP1A2 mRNAs were generally poorly expressed. This work demonstrated for the first time that target mRNAs are expressed in neoplastic tissues of dogs, thereby increasing the knowledge about dog cancer biology and confirming this species as an useful animal model for comparative studies on human oncology.

The accumulation of mutations is a contributing factor in the initiation of premalignant mammary lesions and their progression to malignancy and metastasis. We have used a mouse model in which the carcinogen is the mouse mammary tumor virus (MMTV) which induces clonal premalignant mammary lesions and malignant mammary tumors by insertional mutagenesis. Identification of the genes and signaling pathways affected in MMTV-induced mouse mammary lesions provides a rationale for determining whether genetic alteration of the human orthologues of these genes/pathways may contribute to human breast carcinogenesis. A high-throughput platform for inverse PCR to identify MMTV-host junction fragments and their nucleotide sequences in a large panel of MMTV-induced lesions was developed. Validation of the genes affected by MMTV-insertion was carried out by microarray analysis. Common integration site (CIS) means that the gene was altered by an MMTV proviral insertion in at least two independent lesions arising in different hosts. Three of the new genes identified as CIS for MMTV were assayed for their capability to confer on HC11 mouse mammary epithelial cells the ability for invasion, anchorage independent growth and tumor development in nude mice. Analysis of MMTV induced mammary premalignant hyperplastic outgrowth (HOG) lines and mammary tumors led to the identification of CIS restricted to 35 loci. Within these loci members of the Wnt, Fgf and Rspo gene families plus two linked genes (Npm3 and Ddn) were frequently activated in tumors induced by MMTV. A second group of 15 CIS occur at a low frequency (2-5 observations) in mammary HOGs or tumors. In this latter group the expression of either Phf19 or Sdc2 was shown to increase HC11 cells invasion capability. Foxl1 expression conferred on HC11 cells the capability for anchorage-independent colony formation in soft agar and tumor development in nude mice. The published transcriptome and nucleotide sequence analysis of gene expression in primary human breast tumors was interrogated. Twenty of the human orthologues of MMTV CIS associated genes are deregulated and/or mutated in human breast tumors.

In a previous work, we reported that young transgenic (Tg) mice expressing the intracellular domain of Notch1 (N1(IC)) showed expansion of lin(-) CD24(+) CD29(high) mammary cells enriched for stem cells and later developed mammary tumors. Mammary tumor formation was abolished or greatly reduced in cyclin D1(-/-) or cyclin D1(+/-) N1(IC) Tg mice, respectively. Here, we studied the epithelial cell subsets present in N1(IC)-induced tumors. CD24(-) CD29(int) and CD24(+) CD29(high) cells were found to be present at low numbers in tumors. The latter had the same properties as those expanded in young Tg females, and neither cell population showed tumor-initiating potential nor were they required for maintenance of tumors after transplantation. CD24(int) CD29(int) cells were identified as tumor-initiating and mammosphere-forming cells and represent a large percentage tumor cells in this model. Their number was significantly lower in tumors from cyclin D1(+/-) N1(IC) Tg mice. Using cyclin D1 shRNA knockdown, we also show that N1(IC)-induced tumor cells remain addicted to cyclin D1 for growth and survival. Interestingly, at lower levels of cyclin D1 or after transplantation in the presence of normal mammary cells, these N1(IC)-expressing tumor cells reverted to a state of low malignancy and differentiate into duct-like structures. They seem to adopt the fate of bi-potential stem/progenitor cells similar to that of the expanded CD24(+) CD29(high) stem/progenitor cells from which they are likely to be derived. Our data indicate that decreasing cyclin D1 levels would be an efficient treatment for tumors induced by N1 signaling.

The colony of wild mice, named Jyg, has been shown to express an exogenous mouse mammary tumor virus (Jyg-MMTV). This virus induces mammary tumors in its natural host at a high incidence (≈ 80%) resulting from insertion mutations in Notch-4 (43%), Wnt-1 (26%), and Fgf-3 (13%). Since the activation of Notch-4 is not common in mammary tumors of standard laboratory strains of mice infected with various MMTV strains, we examined the consequences of Jyg-MMTV infection in BALB/c and C57BL/6 mice. The results show that Jyg-MMTV induces mammary tumors in both mouse strains, but the incidence of mammary tumors in BALB/c mice is greater than in C57BL/6 mice. Surprisingly, however, none of the 75 mammary tumors, analyzed both by Southern and Northern hybridizations, showed insertion mutations in or expression of Notch-4 . In contrast, both Wnt-1 and Fgf-3 were found to be involved in these tumors. Our findings may suggest, among other possibilities, the existence of a structural difference(s) between laboratory and wild mice at the Notch-4 locus that regulates the integration of Jyg-MMTV proviral DNA.

Background: Mammary tumors are a type of neoplasia that are most commonly found in female dogs and are mostly malignant. The aim of this study, performed in the Laboratory of Veterinary Pathology of the Federal University of Uberlândia (LVP-FUU) from 2004 to 2014, was to determine the prevalence of mammary tumors in bitches and to verify the relationship between the epidemiological factors (age and breed) and clinicopathological aspects (ulceration, tumor size, and malignancy) in the occurrence of tumors.Materials, Methods & Results: A retrospective study was carried out using histopathological information retrieved from the LPV-UFU database. We collected the information on age and breed of female dogs, as well as about the location, macroscopic aspects, and histological diagnosis of mammary lesions. Only female dogs were considered for this study; a total of 911 histopathological protocols (with only one diagnosis) were analyzed along with 36 protocols that presented more than one diagnosis of mammary tumor. The age of animals ranged from one to 20 years, and the mean age was 9.99 years. The most affected breeds of dogs were: Cross breed (39.56% - 288/728) and Poodle (20.19% - 147/728). The inguinal glands were most affected by the malignant tumors (P < 0.05). A prevalence of tumors bigger than 5 cm in diameter (T3) was observed in the elderly animals (P = 0.0154) and in the inguinal mammary glands (P = 0.044). Simple carcinoma was the most frequent histological type.Discussion: Research shows that more than 40% of the tumors in bitches are located in the mammary glands, emphasizing the importance of this type of neoplasia in female dogs. Mammary tumors develop more frequently in the middle-aged and elderly bitches, with the highest occurrence being in the age range of 8 and 10 years, corroborating our observation in the present study that the mean age of bitches was 9.99 years. In this survey, a higher incidence was observed in mongrel bitches compared to that in the Poodle breed. Some authors affirm that there is no racial predisposition for the occurrence of this pathology; however, a compilation of data suggests a predisposition of at least 10 breeds, with the involvement of an as yet unidentified genetic component. Of these, six breeds (Poodle, Cocker Spaniel, Pointer, Maltese, Yorkshire Terrier, and Dachshund) were found to be predisposed to mammary tumors in this study. The percentage (49.23%) of malignant tumors found in the inguinal glands is consistent with the findings reported in literature, and might be associated with a greater amount of parenchyma, abundance of hormone receptors in these glands, and vascularization provided by the caudal superficial epigastric artery and vulvar branches of external pudendal artery. Tumor size is considered to be a prognostic factor and tumors ≤ 3 cm in diameter (T1) have a better prognosis. Consequently, the prevalence of tumors ≥ 5 cm in diameter (T3) in elderly animals is probably related to malignancy of the lesions, because tumors usually progress to a worse histological grade with time. The higher occurrence of T3 in inguinal glands might be related to the abundance of parenchyma and/or hormonal receptors in them. As in the present study, data from literature refer to the superiority of malignant histological types, with prevalence varying between 68 and 91%. When prolonged, the time between the onset of tumor and clinical evaluation may be a determinant in the progression from benign to malignant tumors. Among the malignant neoplasms, simple carcinoma was observed to be prevalent, followed by mixed tumors with carcinoma, in agreement with the results of several studies. It is concluded that mammary tumors are more prevalent in older mongrel dogs and Poodle. Attention should be paid to inguinal mammary tumors, because these are mainly malignant.

A comprehensive chronic toxicity and carcinogenicity study was conducted on a series of Aroclors (1016, 1242, 1254, and 1260). Each Aroclor was assessed at multiple dietary concentrations, ranging from 25 to 200 ppm, for 24 months in male and female Sprague-Dawley rats. Liver toxicity was indicated by elevated serum enzyme activity (AST, ALT, and GGT), elevated serum cholesterol concentration, decreases in hematologic parameters (RBC, Hb, and Hct), hepatocellular hypertrophy, an increased incidence of altered hepatocellular foci, and an increased incidence of hepatocellular neoplasms (primarily adenomas). Liver toxicity was distinctly more severe in females than in males. The incidence of hepatocellular neoplasms was highly sex-dependent (females >> males), differed between Aroclor mixtures and, for females, increased with dose and followed the general incidence pattern of Aroclor 1254 > Aroclor 1260 approximately Aroclor 1242 > Aroclor 1016. A significant response (p < 0.05) in males was seen only for the high dose of Aroclor 1260. A small increase in the incidence of thyroid gland follicular cell adenomas was noted in males for Aroclors 1242, 1254, and 1260, with the incidence being uniform across dose groups and Aroclor mixtures. For females, increased survival relative to controls was observed for all Aroclor treatment groups. A significantly decreased trend in the incidence of mammary gland neoplasms compared to control was also noted for females receiving Aroclors 1242, 1254, and 1260.

A cytogenetic study of canine breast carcinomas was performed in order to identify the occurrence of chromosomal abnormalities. Samples of spontaneous canine mammary tumors were submitted for histopathological evaluation and for cytogenetic analysis. Hematoxylin and eosin staining was used for the former and conventional Giemsa staining and NOR banding were performed for the latter. Chromosomal breaks and/or gaps affecting autosomes and sex chromosomes were seen in 5 of a total of 14 cases. The percentage of metaphases with abnormal chromosomes was 61%, the average number of metaphase`s chromosomes affected was 1.26, while a media of 1.47 breaks and/or gaps was seen per metaphase. These alterations were observed in complex and simple carcinomas. We propose to include this type of cytogenetic study in addition to routine techniques in order to improve the diagnosis and prognosis prediction., Se realizó un estudio citogenético de carcinomas de mama en hembras caninas con el fin de identificar la ocurrencia de anomalías cromosómicas. Las muestras se obtuvieron de neoplasias mamarias espontáneas y fueron sometidas a evaluación histopatológica y análisis citogenético. Para el primero se utilizó la tinción de hematoxilina y eosina y para el segundo la coloración convencional de Giemsa y bandeo NOR. En 5 oportunidades, de un total de 14 casos estudiados, se observaron quiebres y/o gaps afectando autosomas y cromosomas sexuales. La proporción de metafases verificada en cromosomas anormales fue de 61%, el número promedio de cromosomas afectados por metafase fue de 1,26, mientras que la media de quiebres y/o gaps por metafases fue de 1,47. Estas alteraciones se observaron en carcinomas complejos y simples. Se propone incorporar este tipo de estudio citogenético a las técnicas de rutina con el fin de complementar el diagnóstico y pronóstico de la afección., Centro de Investigaciones Inmunológicas Básicas y Aplicadas

Background: Mammary tumors are extremely common in cats and have high metastatic rates with poor prognosis. The main objective of the present study was to evaluate the disease free interval and survival in cats undergoing radical mastectomy as sole therapy.Materials, Methods & Results: Twenty cats with mammary tumors and no evidence of distant metastasis were studied. General health and concomitant diseases were assessed by clinical and hematological examination. Thoracic radiographs and abdominal ultrasonography were performed to evaluate thoracic and abdominal metastases. All cats underwent chain mastectomy, which was unilateral when tumor was present in one mammary chain, and bilateral in steps if tumors were present in both mammary chains. Intact cats were spayed. An elliptical incision was made around the mammary chain with a three centimeter margin around tumor. Regional lymph node was removed. Mean age was ten years, and 14 cats were mixed breed, three were Persian and two were Siamese. Fifteen cats were spayed at tumor diagnosis, but only three had been spayed before one year old. The inguinal mammary glands were the most affected, followed by abdominal and thoracic glands. Histopathology diagnosed well-differentiated adenocarcinoma in eight cases, moderately differentiated adenocarcinoma in nine cases, poorly differentiated adenocarcinoma in two cases and carcinoma in situ in one case. Most tumors were grade II, and regional lymph node metastasis was present in two cases. Disease free interval ranged from 120 to 1800 days, with an average of 678 days. Four cats had tumor local recurrence and six developed lung metastasis. The survival time ranged from seven to 1800 days, with an average of 768 days. Twelve cats are still alive with no tumor recurrence.Discussion: The average age of onset of mammary carcinomas in cats was ten years old, similar to previous studies. Siamese cats have more risk of developing this disease, but mixed breed cats were frequent in this study. Intact or late spayed cats are predisposed to mammary tumors because of hormonal stimulation, the same was observed in this study. Inguinal and abdominal glands were most affected, similar to other reports. The histopathologic diagnosis was adenocarcinoma in most cases of this study, mostly grade II tumors, which was also observed in previous papers. Regional lymph nodes (axillary or inguinal) should always be removed during mastectomy in cats, as regional metastasis at diagnosis is common, even when not clinically palpable, as was observed in two cases. Distant metastasis occurs most often to the lungs, leading to severe dyspnea. In this study, four cats had local tumor recurrence and six developed lung metastasis. Aggressive and early surgical intervention is the treatment of choice for feline mammary tumors. Unlike dogs (where conservative mammary resections are appropriate in some cases), radical chain mastectomy is recommended for feline mammary tumors, as significantly reduces the risk of local recurrence. In this study, all animals underwent radical mastectomy, without previous cytology or biopsy. Survival is variable between studies, ranging from 220 to 1408 days. Several factors may be involved in disease free intervals and survival times, as tumor size, tumor histological grade, presence of metastasis at diagnosis, type of surgery performed, presence of concomitant diseases and adjuvant chemotherapy. In this study, mean survival time was 768 days and 12 cats are still alive and in follow-up, which may increase this number. This study supports that, if treated early and agressively, cats with malignant mammary tumors can have long survival after chain mastectomy.

Background This study aimed to evaluate the relationship between the molecular phenotype of the primary mammary tumor and its related lymph node metastasis in the dog to develop prognostic-predictive models and targeted therapeutic options. Results Twenty mammary tumor samples and their lymph node metastases were selected and stained by immunohistochemistry with anti-estrogen receptor (ER), -progesterone receptor (PR), -human epidermal growth factor receptor 2 (c-erbB-2), -cytokeratin 5/6 (CK 5/6), -cytokeratin 14 (CK14), -cytokeratin 19 (CK 19) and -protein 63 (p63) antibodies. Four phenotypes (luminal A, luminal B, c-erbB2 overexpressing and basal-like) were diagnosed in primary tumors and five (luminal A, luminal B, c-erbB-2 overexpressing, basal-like and normal-like) in the lymph node metastases. Phenotypic concordance was found in 13 of the 20 cases (65%), and seven cases (35%) showed discordance with different lymph node phenotypic profile from the primary tumor. Conclusions The phenotype of the primary tumor assumes a predictive-therapeutic role only in concordant cases, meaning that both the primary tumor and its lymph node metastasis should be evaluated at the same time. A treatment plan based only on the primary tumor phenotype could lead to therapeutic failures if the phenotype of the lymph node metastasis differs from that of the primary tumor.

Cytological diagnosis is not generally conclusive enough to identify histopathological malignancy in canine mammary tumors (CMTs). To establish cytological examination using fine needle biopsy (FNB) samples, gene expressions of hormonal receptors, human epidermal growth factor receptor 2 (HER2), and transcription regulators (Special AT-rich binding protein 1: SATB1 and Snail) were investigated in both tissue and FNB samples of CMTs. In tissue samples of malignant CMTs, especially invasive ones, low expressions of hormonal receptors and high expressions of SATB1 and Snail were detected. On discriminant analysis of tissue samples, 73.2% of CMTs were correctly classified according to histopathological examinations. In FNB samples of malignant CMTs, low expressions of hormonal receptors were detected. On discriminant analysis of FNB samples, 74.2% of CMTs were correctly classified according to histopathological examination. In conclusion, FNB gene expressions had a utility for diagnosis of CMTs malignancy in some degree. By researching more sensitive genes for malignant CMTs, the gene examination of FNB samples from CMTs will become a useful diagnostic tool that can be performed easily without anesthesia and could predict tumor malignancy and invasion prior to surgical removal.

Introduction The limited ability of current treatments to control metastasis and the proposed antitumor properties of specific nutrients prompted us to examine the effect of a specific formulation (nutrient supplement [NS]) of lysine, proline, arginine, ascorbic acid, and green tea extract in vivo on the development of N-methyl-N-nitrosourea (MNU)-induced mammary tumors in rats. Methods A single intraperitoneal dose of MNU was injected into each of 20 female Sprague–Dawley rats (aged 50 days) to induce tumors. Two weeks after MNU treatment, a time by which the animals had recovered from MNU-induced toxicity, the rats were divided into two groups. Rats in group 1 (n = 10) were fed Purina chow diet, whereas those in group 2 (n = 10) were fed the same diet supplemented with 0.5% NS. After a further 24 weeks, the rats were killed and tumors were excised and processed. Results NS reduced the incidence of MNU-induced mammary tumors and the number of tumors by 68.4%, and the tumor burden by 60.5%. The inhibitory effect of NS was also reflected by decreased tumor weight; the tumor weights per rat and per group were decreased by 41% and 78%, respectively. In addition, 30% of the control rats developed ulcerated tumors, in contrast to 10% in the nutrient supplemented rats. Conclusion These findings suggest that the specific formulation of lysine, proline, arginine, ascorbic acid, and green tea extract tested significantly reduces the incidence and growth of MNU-induced mammary tumors, and therefore has strong potential as a useful therapeutic regimen for inhibiting breast cancer development.

purified daidzein at 200 mg/kg diet Previous studies have shown an inhibitory effect of soy on mammary carcinogenesis, but it is unclear which component of soy provides this beneficial effect. The present study was undertaken to compare the anti-tumor effects of soy protein isolate and those of its isoflavones: genistein and daidzein. Six groups of female Sprague-Dawley rats were fed modified corn starch AIN76A diets supplemented with: no additional agents (control) purified genistein at 200 mg/kg diet a combination of genistein and daidzein at 100 mg/kg diet each soy protein isolate enriched in isoflavones (SPI+) or soy protein isolate depleted of isoflavones (SPI-). Mammary carcinomas were induced by 7,12-dimethylbenz[a]anthracene (DMBA) injected one week after the animals started eating the experimental diets. At the end of the study (120 days post-DMBA treatment), no significant differences were found among the six groups with respect to tumor incidence or survival. However, there was a significant (p < 0.05) reduction in tumor multiplicity in the daidzein (5.45) and SPI+ (5.45) groups, when compared to the control group (8.05). The most effective diet was the SPI-, which produced a highly signifi-cant (p < 0.01) reduction in tumor multiplicity (4.05). Tumor latency was increased from 53 days in the control group to 68 days in the daidzein group and to 72 days in the SPI-group. Both SPI groups, but not the genistein or daidzein groups, up-regulated transcriptional expression of the anti-oxidant enzymes NAD(P)H:quinone reductase (QR) and glutathione S-transferase (GST) Ya2. These results suggest that the mode of chemopreventive action of soy protein isolate is distinct from that of the main soy isoflavones. Furthermore, isoflavone-depleted soy may be more beneficial than isoflavone-enriched soy in preventing mammary tumors in these experimental animals. 40 24 34 Cited By :8

Background: The hypothalamic luteinizing hormone-releasing hormone (LHRH) is well known for its role in the control of pituitary gonadotropin secretion and it has demonstrated a direct antiproliferative effect on some cancer cell lines of LHRH and its synthetic analogs. The study was designed to assess whether administration of the LHRH analog (goserelin) has any effect on the expression of the vascular endothelial growth factor (VEGF) and the epidermal growth factor receptor (EGFR) in rats with N-nitroso-N-methylurea (NMU)-induced-mammary tumors in vivo. Materials and Methods: The animals with tumors were assessed after acute or chronic treatment with goserelin, and in all the animals VEGF and EGFR expression was examined both in plasma and tumor homogenates by enzyme immunoassay. Results: The basal plasma values of VEGF were lower in the healthy control group than in rats with NMU-induced tumors ( P = 0.025). Following acute treatment with goserelin, VEGF expression in plasma increased above basal levels after 60 min ( P = 0.05) and dropped during chronic treatment. Likewise, in the tumor homogenate the mean VEGF expression was higher at 60 min post-goserelin administration than the basal levels, although VEGF expression then diminished at 90 min. Plasma EGFR expression was higher in rats with NMU-induced tumors than in healthy controls ( P < 0.01). Conclusions: The results allow us to conclude that goserelin may exert a short-term stimulatory effect on the release of VEGF, as well as a long-term inhibitory effect on VEGF but not EGFR expression.

Myofibroblasts and extracellular matrix protein tenascin-C (Tn-C) are known to be implicated in cancer progression in human cancer. In feline mammary tumors that are a suitable model for human breast cancer, however, little is known about stromal myofibroblasts and no information is available on the expression of Tn-C. Feline samples of normal mammary glands and proliferating mammary lesions were routinely processed and serial sections were cut and immunostained with anti-α-smooth muscle actin (α- SMA) or Tn-C antibody. Myofibroblasts were not included in the stroma of 90% (9/10) of normal mammary gland tissues, 92% (12/13) of adenosis, and 63% (5/8) of simple adenomas. On the other hand, all 40 simple carcinomas contained stromal myofibroblasts to a varied extent. Tn-C expression was detected in the stroma of 92% (37/40) of carcinomas, and its global distribution almost coincided with that of myofibroblasts. In addition, Tn-C immunoreactivity was occasionally observed in the basement membrane zone around ducts in some cases of normal mammary glands and benign lesions, but barely observed in the stroma. These results suggest that stromal myofibroblasts may be a major cellular source of Tn-C and be involved in malignant progression of feline mammary tumor.