Molecular and Pathobiology of Canine Mammary Tumour: Defining a Translational Model for Human Breast Cancer.

Canine mammary tumours (CMT) have histological, clinicopathological and molecular resemblances to human breast cancer (HBC), positioning them as viable models for studying the human disease. CMT initiation and progression occur spontaneously in immune-competent animals, which challenge the suggested limitations of genetically modified mice, also enabling the evaluation of immunotherapies in canine patients. Dogs have shorter life expectancy compared to humans, and cancer advances more rapidly in this species. This makes it possible to perform studies about the clinical efficacy of new therapeutic modalities in a much shorter time than in human patients. The identification of biomarkers for tumour subtypes, progression and treatment response paves the way for the development of novel therapeutic and diagnostic approaches. This review addresses the similarities between CMT and HBC and the molecular signatures identified in CMT samples that have been explored to date. We proposed a detailed molecular exploration of the CMT stroma using state-of-the-art methods in transcriptomics and proteomics. Using CMT as an analog for HBC not only helps to understand the complexities of the disease, but also to advance comparative oncology to the next level to prove the claim of dogs as a valid translational model.

Expression of acetylated histones H3 and H4 and histone deacetylase enzymes HDAC1, HDAC2 and HDAC6 in simple mammary carcinomas of female dogs.

Histone deacetylation is an important mechanism involved in human breast cancer tumorigenesis and recent veterinary oncology studies also demonstrate a similar relationship in some canine neoplasms. The use of HDAC inhibitors in vitro and in vivo has demonstrated antitumor action on several strains of human and animal cancers. The present study aims to correlate the expression of H3K9Ac, H4K12Ac, HDAC1, HDAC2 and HDAC6 in simple mammary carcinomas in dogs with clinicopathological parameters and overall survival time. To this end, 61 samples of simple breast carcinomas were analyzed by the immunohistochemistry technique with subsequent validation of the antibodies by the Western Blot technique. The expressions obtained via a semi-quantitative way were categorized by assigning scores and classified into high or low expressions according to the given score, except for HDAC6, when the marking percentage was considered and subdivided into high and low expressions using the median value. For statistical analysis, the chi-square test or Fisher exact test were used as univariate analysis and correspondence analysis as a multivariate test, in addition to the Kaplan-Meier survival analysis. In the studied samples, the highest frequencies were determined for the high expression proteins H4K12Ac (88.5%), HDAC2 (65.6%) and HDAC6 (56.7%) and the low expression proteins H3K9Ac (73.8%) and HDAC1 (54.1%). An association between the low expression of HDAC1 and the presence of lymph node metastasis (p = 0.035) was indicated by univariate analysis while the high expression of HDAC1 was associated with favorable prognostic factors, such as the absence of lymph node metastasis and low mitotic index by multivariate analysis. Also, by multivariate analysis, the low expression of HDAC6 was correlated with the low expression of Ki67, smaller tumors, and better prognosis factors as well. Protein expression was not correlated with patients' overall survival time (p > 0.05). The high expressions of HDAC2 and HDAC6 in mammary carcinomas in female dogs may be useful information for research involving therapeutic targets with iHDACs since their inhibition favors hyperacetylation and transcription of tumor suppressor genes.

Breast cancer sub-types display heterogeneity in gene amplification and mRNA expression of the anti-apoptotic members of BCL2 family.

BACKGROUND: Progress in therapies and improved outcomes in recent decades have followed a better understanding of breast cancers pathogenesis and their heterogeneity but new treatments are needed especially for metastatic disease which remains incurable. Inhibition of apoptosis is a hallmark characteristic of cancer and can be targeted for therapy. METHODS: The five anti-apoptotic members of the BCL2 family are at the core of apoptosis execution and are involved in apoptosis evasion of transformed cells. Genetic lesions as well as mRNA regulation of these members in breast cancer and its sub-types and implications for survival outcomes were investigated using data from various publicly available databases. RESULTS: Genes encoding for anti-apoptotic BCL2 proteins are rarely mutated in breast cancer and copy number alterations are observed only in MCL1 gene which is amplified in a minority of breast cancer ranging from 1.6% to 18.7% in breast cancers. Over-expression of BCL2, BCL-X and MCL1 is observed in luminal A cancers, while cases of luminal B and basal breast cancers display mRNA up-regulation of BCL-X and MCL1, respectively. Basal cancers possess also more frequently than other sub-sets MCL1 amplifications. Survival outcomes are not significantly different in cancers with higher expression of anti-apoptotic BCL2 mRNAs. CONCLUSION: Therapeutic targeting of the apoptotic process in breast cancer sub-types will be improved by a detailed understanding of the core players in the process, including anti-apoptotic BCL2 family proteins. A sub-set of breast cancers harbor amplifications of MCL1 and dysregulations of expression of most family members that could affect the sensitivity to their inhibition by altering the cell's apoptotic threshold.

The development of molecular typing in canine mammary carcinomas.

Mammary tumors are the most frequent neoplasia in old female dogs and present challenges in diagnosis and prognosis owing to heterogeneity. Along with the rapid development of biotechnology, the molecular subtyping of canine mammary carcinomas has been researched, and provides an important reference basis for diagnosis, treatment, prognosis, and even prediction of recurrence rate. Therefore, the molecular classification of canine mammary carcinomas has gained a broad clinical application prospect. However, the existing molecular markers of canine mammary carcinomas are still unable to meet the expanding clinical needs with poor clinical feasibility. Thus, it is urgent to develop more applicable biomarkers appropriate for personalized treatment modalities. At present, the molecular typing of canine mammary carcinomas is not fully understood, and it is first reviewed in this study.

Identification of EDIL3 biomarkers as a biomarker and potential therapeutic target of canine mammary carcinomas based on integrated bioinformatics analysis.

As the fierce battle with cancer is now expanding to companion animals, effective treatment of canine mammary carcinomas (CMT), as the most frequently diagnosed tumor in intact dogs, is becoming a crucial issue. Although many studies have been carried out concerning the clinical application of mammary tumor biomarkers, no ideal biomarker has yet been identified in CMT. Therefore, in this work, we develop EDIL3 as a CMT biomarker having significantly higher expression levels in CMT samples compared to those in controls in GSE13754, GSE22516 and GSE25586 datasets, which suggest that EDIL3 is a gene related to tumorigenesis. We also validate the significantly high expression levels of EDIL3 in CMT samples using our sequencing canine samples. ROC curves analysis showed that in comparison with HER2 reported as predictive factor for CMT patients, EDIL3 exhibits stronger power for CMT recognizing. Moreover, we also find that low expression levels of EDIL3 are associated with advanced grade status in CMT, which indicate a negative correlation between EDIL3 and CMT development. GSEA is employed to unveil the underlying mechanism of this interesting function of EDIL3 in CMT development, and it suggests that the expression level of EDIL3 is related to immunity pathway. Finally, CIBERSORT analysis is employed in this study in order to further explore the relationship between EDIL3 and immunity in CMT, and it unveils that EDIL3 has stably positive correlation with follicular helper T cells and negative correlation with NK resting cells in CMT. Our study develops EDIL3 as a biomarker for assisting CMT distinction, highlighting the relationship of EDIL3 with the infiltrations of follicular helper T cells and NK resting cells, which could be a new potential therapy target for CMT and provide bioinformatics basis for later clinical experiment validation.

Expression of LIN28A/B and Let-7 miRNAs in canine mammary carcinomas / Expressão de LIN28A/B e Let-7 miRNAs em carcinomas mamários caninos

LIN28 is a RNA-binding protein including two highly conserved homologous, LIN28A and LIN28B. Proto-oncogenes such as LIN28A and LIN28B are generally targeted by the let-7 miRNAs in different types of human cancers. Here, we determined the expression of LIN28A in canine mammary tumor samples and the LIN28/let-7 pathway in canine mammary cell lines. In those cell lines, we identified a functional LIN28/let-7 pathway which exhibited high expression of let-7 members and low expression of its targets, including LIN28A and LIN28B. However, the mammary carcinoma tissue samples showed a frequent expression of LIN28A being expressed mainly in the epithelial cells. No association was observed between LIN28A expression and histopathological classification and grade, TNM and survival time. Our results suggested a possible role of the LIN28A protein in the development of canine mammary carcinomas due to the high frequency observed in the tumor samples (28 of 32). The in vitro experiments suggested that the LIN28/let-7 pathway is active in the tumor cells evaluated. However, more studies are necessary to elucidate the exact role of LIN28/let-7 pathway in canine mammary carcinomas.

LIN28 é uma proteína de ligação ao RNA, com duas formas homólogas altamente conservadas, LIN28A e LIN28B. Os proto-oncogenes LIN28A e LIN28B são regulados pela família de miRNAs let-7 em diferentes tipos de cânceres em humanos. No presente trabalho, o objetivo foi determinar a expressão de LIN28A em amostras de tumor mamário de cadelas e a via LIN28/let-7 em linhagens celulares mamárias caninas. Nestas linhagens, através das técnicas de qPCR e RNAseq, foi identificado que a via LIN28/let-7 apresenta-se funcional, com alta expressão dos membros da família let-7 e baixa expressão de seus alvos, entre eles LIN28A e LIN28B. No entanto, as amostras de tecidos de carcinomas mamários caninos demonstraram expressão frequente de LIN28A, sendo observada principalmente em células epiteliais. Não foram observadas associações entre expressão de LIN28A com classificação e gradação histopatológicas, TNM e tempo de sobrevida. Nossos resultados sugerem uma possível relação da proteína LIN28A no desenvolvimento de carcinomas mamários caninos devido à alta frequência observada nas amostras tumorais (28 de 32). Os experimentos in vitro sugerem que a via LIN28/let-7 é ativa nas linhagens celulares caninas avaliadas. Entretanto, estudos funcionais ainda são necessários para elucidar a função exata da via LIN28/let-7 nos carcinomas mamários caninos.

LTX-315-enabled, radiotherapy-boosted immunotherapeutic control of breast cancer by NK cells.

LTX-315 is a nonameric oncolytic peptide in early clinical development for the treatment of solid malignancies. Preclinical and clinical evidence indicates that the anticancer properties of LTX-315 originate not only from its ability to selectively kill cancer cells, but also from its capacity to promote tumor-targeting immune responses. Here, we investigated the therapeutic activity and immunological correlates of intratumoral LTX-315 administration in three syngeneic mouse models of breast carcinoma, with a focus on the identification of possible combinatorial partners. We found that breast cancer control by LTX-315 is accompanied by a reconfiguration of the immunological tumor microenvironment that supports the activation of anticancer immunity and can be boosted by radiation therapy. Mechanistically, depletion of natural killer (NK) cells compromised the capacity of LTX-315 to limit local and systemic disease progression in a mouse model of triple-negative breast cancer, and to extend the survival of mice bearing hormone-accelerated, carcinogen-driven endogenous mammary carcinomas. Altogether, our data suggest that LTX-315 controls breast cancer progression by engaging NK cell-dependent immunity.

Impact of treatment schedule on the efficacy of cytostatic and immunostimulatory agents.

Radiation therapy (RT) and cyclin-dependent kinase 4/6 (CDK4/6) inhibitors mediate poorly overlapping cytostatic and immunostimulatory effects, suggesting that combinatorial regimens may enable supra-additive tumor control. Our preclinical findings demonstrate that administration schedule stands out as a major determinant of efficacy when RT and CDK4/6 inhibitors are combined for breast cancer therapy.

Genetic variants of BRCA1 and BRCA2 genes in cats with mammary gland carcinoma.

Mammary tumours are the first and third most incident neoplasm in women and cats, respectively. Approximately 85% of feline mammary gland tumours are malignant and aggressive, especially the triple-negative and HER-2+ molecular subtypes. Triple-negative basal-like feline mammary carcinomas (FMCs) are considered suitable models due to the clinical and morphological similarities with human basal-like triple-negative breast cancer (TNBC). In women, TNBC has a poor prognosis and is often associated with mutations in the tumour suppressor genes BRCA1 and BRCA2. In light of this, the aim of the present investigation was to screen somatic and germline variants of BRCA1 and BRCA2 in nine female cats bearing FMCs. Matched whole blood and FMC samples were obtained for genetic analysis. Additional tumour samples were obtained for histopathological and immunohistochemical evaluation. Genomic DNA was isolated and 27 exonic regions of BRCA1 and BRCA2 genes were amplified and screened by next-generation sequencing. A somatic variant with high functional impact was found in exon 11 of BRCA2 at a frequency of 4.34% in one FMC-bearing cat. Four germline variants with moderate impact were detected in three of the nine FMC-bearing cats and were restricted to exon 9 of BRCA1. It is concluded that the germline genetic variants found in one-third of FMC-bearing animals might be associated with a higher risk of hereditary mammary carcinogenesis.

Serum Metabolomic Analysis of Feline Mammary Carcinomas based on LC-MS and MRM Techniques.

INTRODUCTION: To date, there have been no panoramic studies of the serum metabolome in feline mammary carcinoma. As the first such study, metabolomics techniques were used to analyse the serum of cats with these tumours. Three important metabolic pathways of screened differential metabolites closely related to feline mammary carcinomas were analysed to lay a theoretical basis for further study of the pathogenesis of these carcinomas. MATERIAL AND METHODS: Blood in a 5-8 mL volume was sampled from twelve cats of the same breed and similar age (close to nine years on average). Six were feline mammary carcinoma patients and six were healthy. L glutamate, L alanine, succinate, adenine, hypoxanthine, and inosine were screened as were alanine, aspartate, and glutamate metabolism, the tricarboxylid acid (TCA) cycle, and purine metabolism. Data were acquired with LC-MS non-target metabolomics, multiple reaction monitoring target metabolomics, and multivariate statistical and bioinformatic analysis. RESULTS: Expression of five of the metabolites was upregulated and only inosine expression was downregulated. Up- and downregulation of metabolites related to glycometabolism, potentiation of the TCA cycle, greater content of lipid mobilisation metabolites, and abnormality of amino acid metabolism were closely related to the occurrence of the carcinomas. CONCLUSION: These findings provide a new direction for further study of the mechanisms associated with cat mammary neoplasms.

Tumor Infiltrating Lymphocytes in Pet Rabbit Mammary Carcinomas: A Study with Relevance to Comparative Pathology.

Tumor infiltrating lymphocytes (TILs) serve as prognostic biomarker in human breast cancer. Rabbits have the potential to act as animal model for human breast cancer, and close similarities exist between the rabbit and human immune system. The aim of this study is to characterize TILs in pet rabbit mammary carcinomas and to statistically correlate results with histological and immunohistochemical tumor characteristics. Microscopic evaluation of TILs was performed in hematoxylin and eosin stained sections of 107 rabbit mammary carcinomas according to international guidelines for human breast cancer. Data on histological features of malignancy, estrogen and progesterone receptor status and calponin expression were obtained from the data base. This study revealed a statistical association between stromal TILs in the central tumor (CT) and infiltrative margin. Higher maximal percentages of stromal TILs at the CT were statistically correlated with decreased mitotic count and lower tumor grade. An increased number of calponin positive tumor cells was statistically associated with a lower mitotic count and a higher percentage of stromal TILs. Results suggest that higher percentages of stromal TILs are useful biomarkers that may point toward a favorable prognosis in rabbit mammary carcinomas and support the concept of the use of rabbits for translational research.

Osteopontin expression and its relationship with prognostic biomarkers in canine mammary carcinomas / Expressão de osteopontina e sua relação com biomarcadores prognóstico nos carcinomas mamários caninos

Osteopontin is a glycophosphoprotein implicated in different physiologic and pathologic processes and is known to be involved in progression and metastasis of various cancers in humans, but this relation is still little explored in the veterinary. The aim was to evaluate the expression of osteopontin in canine mammary carcinomas and its relation with well-established canine mammary tumor biomarkers. For that, expression of OPN, EGFR, HER2, and c-Kit were evaluated along with Ki67 rate in 43 mammary carcinomas. Osteopontin was demonstrated to be expressed by neoplastic epithelial cells in all carcinomas as well as in stromal cells from the tumor microenvironment. Relation between high osteopontin expression and EGFR positivity (P<0.001) and HER2 overexpression (P=0.012) was demonstrated. In conclusion, high OPN expression seems to be related to poor prognosis and MAPK pathway activation, given the association with EGFR and HER2, members of the MAPK signaling pathway.(AU)

A osteopontina é uma glicofosfoproteina implicada em diferentes processos fisiológicos e patológicos, sendo conhecida por estar envolvida na progressão e metástase de vários cânceres nos humanos, no entanto, essa relação é ainda pouco explorada na veterinária. O objetivo deste trabalho foi avaliar a expressão da osteopontina nos carcinomas mamários caninos e sua relação com biomarcadores bem estabelecidos para esta neoplasia. Para isto, foi avaliada a expressão de OPN, EGRH, HER2 e c-Kit juntamente com a taxa de Ki67 em 43 carcinomas mamários. A osteopontina foi expressa pelas células epiteliais neoplásicas em todos os carcinomas, assim como, nas células estromais do microambiente tumoral. Foi demonstrada uma relação entre uma alta expressão de osteopontina e positividade para EGFR (P<0.001) e superexpressão de HER2 (P=0.012). Em conclusão, alta expressão de OPN parece estar relacionada com mau prognóstico e ativação da via MAPK, devido a sua associação com EGRF e HER2, os quais são membros desta via de sinalização.(AU)

Developing and testing prognostic bio-scoring systems for canine mammary gland carcinomas.

Canine mammary carcinomas (CMC) represent a range of histolopathological subtypes with diverse biological behaviours. Several individual factors, including stage, grade, subtypes and presence of invasion, predict outcome. Less is known how these factors interact and impact prognosis. The purpose of this work was to develop and test comprehensive bio-scoring systems in CMCs. Clinical and histopathological data from 127 dogs with MCs treated through two prospective studies were obtained. All dogs underwent standardized pre-surgical staging, treatments and regular follow-up visits. All tumours were evaluated, classified and graded according to published guidelines. Time to primary metastasis was the main endpoint in this study. Two bio-scoring systems were developed: The multivariate scoring (MVS) was based on traditional statistical analysis where only factors significant in the multivariate analysis (tumour size and grade) were kept for the final model. The refined flexible scoring (RFS) system was based on results from subgroup analysis, which guided the development of a flexible system. Progressive worsening prognosis was observed with increasing bio-scores in both systems. MVS: Median primary metastasis-free survival (TTM1 days) was not reached in dogs with bio-scores 0 to 5, 10, 15 and 648, 149, 317, in MVS groups 25, 30, 40, respectively. Similarly, TTM1 was not reached in dogs with RFS 0, 1, 2 and 374, 407 and 149, in dogs with bio-scores 3, 4, 5, respectively. However, a more distinct separation between dogs with high risk vs low risk for metastasis was observed with RFS, suggesting superior overall prognostication regarding the risk for metastasis.

Serum evaluation of leptin, IL-6, IGF-1 and estrogen in obese bitches with early stages of mammary carcinoma / Avaliação sérica de leptina, IL-6, IGF-1 e estrógeno em cadelas com excesso de peso e portadoras de carcinomas mamários em estágio inicial

The aim of this study was to relate the serum concentration IL-6, IGF-1, leptin and estrogen in non-castrated bitches with or without overweight and early stage mammary carcinomas. Forty-three bitches were divided into four groups, two groups without mammary carcinomas with and without overweight, and two groups with mammary carcinomas with and without overweight. Overweight bitches, with or without mammary carcinomas, were statistically different from bitches by ideal weight, in relation to ECC, IMCC and body fat percentages (P< 0.0001). There was a positive correlation between ECC and IMCC (P< 0.0001), ECC and % GC (P< 0.0001), and IMCC and % GC (P< 0.0001). A positive correlation was found between serum leptin and IL-6 (P= 0.0451) and leptin and IGF-1 (P= 0.05). A positive correlation (P= 0.0053) between ECC and leptin was found in the analysis of body evaluation methods and serum concentrations, and a negative correlation between ECC and IL-6 (P= 0.0435). Among the fat percentage and the leptin concentration, there was a positive correlation (P= 0.0016), as found between the IMCC and leptin (P= 0, 0209). In this study, no association was observed between excessive weight and the presence of early stage mammary carcinomas.(AU)

Este estudo teve por objetivo relacionar a concentração sérica de IL-6, IGF-1, leptina e estrógeno, em cadelas não castradas com ou sem excesso de peso, e carcinomas mamários em estágio inicial. Quarenta e três cadelas foram divididas em quatro grupos, sendo dois de cadelas sem carcinomas mamários, com e sem excesso de peso, e dois de cadelas com carcinomas mamários, com e sem excesso de peso. Cadelas com excesso de peso, com ou sem carcinomas mamários, foram estatisticamente diferentes de cadelas em peso ideal, em relação às avaliações corporais de ECC, IMCC e percentual de gordura corpórea (P<0,0001). Foi observada uma correlação positiva entre ECC e IMCC (P<0,0001), ECC e %GC (P<0,0001), e IMCC e %GC (P<0,0001). As análises de estrógeno, leptina, IL-6 e IGF-1 não apresentaram diferenças estatísticas entre os grupos. Demonstrou-se correlação positiva entre as concentrações séricas de leptina e IL-6 (P=0,0451) e leptina e IGF-1 (P=0,05). Encontrou-se correlação positiva entre ECC e leptina (P=0,0053) e negativa entre ECC e IL-6 (P=0,0435). Entre o percentual de gordura e leptina encontrou-se correlação positiva (P=0,0016), assim como entre IMCC e leptina (P=0,0209). Neste estudo, não se observou associação entre excesso de peso e a presença de carcinomas mamários em estadio inicial.(AU)

Exploring new biomarkers in the tumour microenvironment of canine inflammatory mammary tumours.

Human inflammatory breast cancer (IBC) and canine inflammatory mammary cancer (CIMC) are the most aggressive forms of mammary cancer. Current research aims to identify new therapeutic targets. Here, we investigated gene expression levels of biomarkers associated with the inflammatory microenvironment. A total of 32 formalin-fixed paraffin-embedded samples of canine mammary carcinoma (CIMC = 26; non-CIMC = 6) were used and their cDNA subjected to quantitative polymerase chain reaction (qPCR) to establish gene expression levels for mediators commonly implicated in linking carcinogenesis with inflammation. Gene expression differences between CIMC and non-CIMC types were obtained for cyclooxygenase 2 (COX-2) (P = 0.004), synuclein gamma (SNCG) (P = 0.006), tribbles 1 (P = 0.025), vascular endothelial growth factor (VEGF) (P = 0.017) and CSF1R (P = 0.045). Among these biomarkers correlations were found, particularly between SNCG and tribbles 1 (r = 0.512, P = 0.001). The efficient metastasis of CIMC is intimately linked to components in the tumour microenvironment. This study suggests that upregulation and correlation of SNCG and tribbles 1 deserves to be further explored.

HER-2, EGFR, Cox-2 and Ki67 expression in lymph node metastasis of canine mammary carcinomas: Association with clinical-pathological parameters and overall survival.

Studies about canine mammary tumors based on single molecular markers probably cannot accurately account for the heterogeneity of this disease, and the investigation of multiple molecular alterations in primary tumors and their metastases, in conjunction, has assumed great importance for the understanding of mammary tumor progression. In the present study, we selected 54 primary mammary carcinomas with lymph node metastasis (T1,2,3N1M0), 29 primary mammary carcinomas without metastasis (T1,2,3N0M0), and 25 canine lymph nodes metastasis to evaluate the immunohistochemical expression of HER-2, EGFR, Cox-2 and Ki67 and its association with clinical-pathological parameters and overall survival. Our results found a concordance between the expression of HER-2 (K coefficient: 0.250), Cox-2 (K coefficient: 0.571), and Ki67 (K coefficient: 0.397) and a discordance between EGFR expression (K coefficient: -0.195) in primary mammary carcinomas and paired lymph node metastasis. Furthermore, a high Ki67 index (>24%), large tumor size and the presence of angiolymphatic invasion in canine primary mammary carcinoma with lymph node metastasis plus the presence of extracapsular extension in lymph nodes metastasis were also related to worse prognoses and shorter overall survival (P<0.05). In conclusion, our study demonstrates that primary mammary carcinomas with high expression of HER-2, Cox-2 and Ki67 also show high expression of these markers in paired lymph node metastasis. Moreover, the expression of these molecular markers in lymph nodes metastasis did not demonstrate a prognostic relevance.

Immunohistochemical Expression of CCR2, CSF1R and MMP9 in Canine Inflammatory Mammary Carcinomas.

BACKGROUND: Canine inflammatory mammary cancer (IMC) and its human counterpart, inflammatory breast cancer, are extremely aggressive types of cancer. Our aim was to characterize immunohistochemical expression of C-C chemokine receptor 2, colony stimulating factor 1 receptor and metalloproteinase-9 in canine IMC versus non-IMC and to analyze associations with clinicopathological variables. MATERIALS AND METHODS: Immunohistochemical staining of CCR2, CSF1R and MMP9 was performed in a series of 25 IMC and 15 non-IMC tumors. RESULTS: No differences in the expression of these biomarkers between IMC and non-IMC were observed. Distinct nuclear subcellular expression of CCR2 was observed in IMC (p<0.001). For IMC, higher CCR2 expression was associated with increased nuclear grade (p=0.037), and higher neoplastic MMP9 expression was associated with fewer mitoses (p=0.022), higher nuclear grade (p=0.047) and increased CSF1R expression (p=0.025). CONCLUSION: Expression of CCR2, CSF1R and MMP9 in canine IMC could contribute to increased nuclear pleomorphism, but the biological mechanisms involved warrant further investigation.

Serum HER2 levels are increased in cats with mammary carcinomas and predict tissue HER2 status.

HER2 is overexpressed in about 30% of feline mammary carcinomas (FMC) and in 15-30% of breast cancers. Women with HER2-positive breast tumors are associated with shorter survival. This study aimed to optimize the detection and quantification of serum HER2 (sHER2) in cats and to evaluate its potential in diagnosing cats with mammary carcinomas (MC) overexpressing HER2. A prospective study was conducted in 60 queens showing MC and 20 healthy animals. Pre-operative serum samples were collected for sHER2 quantification using two immunoassays: ELISA and Dot blot assay. sHER2 levels were compared with tissue HER2 status assessed by immunohistochemistry. Queens with FMC showed significantly higher mean levels of sHER2 by both ELISA and Dot blot assay. A significant difference in the sHER2 levels was also found between cats with HER2-positive MC and those with low-expressing HER2 MC. A significant correlation between sHER2 levels and tumor HER2 status was also found, particularly when ELISA was used (r = 0.58, p < 0.0001). The value of 10 ng/ml was proposed as the optimal cutoff for both immunoassays by ROC analysis. Like in humans, sHER2 levels are increased in cats with MC HER2-positive, strongly suggesting that evaluation of sHER2 levels can be very useful in feline oncology. The results show that ELISA and Dot blot assay can replace the immunohistochemistry technique, due to their efficacy and lower costs for diagnostic purposes and for monitoring the response to anti-HER2 therapies in cats.

Cat Mammary Tumors: Genetic Models for the Human Counterpart.

The records are not clear, but Man has been sheltering the cat inside his home for over 12,000 years. The close proximity of this companion animal, however, goes beyond sharing the same roof; it extends to the great similarity found at the cellular and molecular levels. Researchers have found a striking resemblance between subtypes of feline mammary tumors and their human counterparts that goes from the genes to the pathways involved in cancer initiation and progression. Spontaneous cat mammary pre-invasive intraepithelial lesions (hyperplasias and neoplasias) and malignant lesions seem to share a wide repertoire of molecular features with their human counterparts. In the present review, we tried to compile all the genetics aspects published (i.e., chromosomal alterations, critical cancer genes and their expression) regarding cat mammary tumors, which support the cat as a valuable alternative in vitro cell and animal model (i.e., cat mammary cell lines and the spontaneous tumors, respectively), but also to present a critical point of view of some of the issues that really need to be investigated in future research.