Ha-Young Lim

Analysis of a new histological and molecular-based classification of canine mammary neoplasia.

Canine mammary tumors (CMTs) are morphologically and biologically heterogeneous, prompting several attempts to classify such tumors on the basis of their histopathological characteristics. Recently, molecular-based analysis methods borrowed from human breast cancer research have also been applied to the classification of CMTs. In this study, canine mammary neoplasms (n = 648) occurring in Korea from 2008 to 2011 were analyzed according to the histological classification and grading system proposed by Goldschmidt et al. Furthermore, randomly selected mammary carcinomas (n = 159) were classified according to the molecular subtype using immunohistochemical characteristics. Canine mammary neoplasia accounted for 52.6% (648/1250) of the tumors in female dogs, and 51.7% (340/648) of these were malignant. All of the carcinoma-anaplastic subtypes were grade III tumors (5/5, 100%), while most of the carcinoma-tubular subtypes (15/18, 83.3%) and carcinoma arising in a complex adenoma/mixed-tumor subtype (115/135, 85.2%) were grade I tumors. Tumor cell invasion into lymphatic vessels was most common in the comedocarcinoma, carcinoma-anaplastic, and inflammatory carcinoma subtypes. The most frequently occurring molecular subtype (70/159, 44%) was luminal A. However, the basal-like subtype was the most malignant and was frequently associated with grade III tumors and lymphatic invasion. The carcinoma-solid subtypes were also often of the basal-like subtype. Reclassification of CMTs using the newly proposed histopathological classification system and molecular subtyping could aid in determining the prognosis and the most suitable anticancer treatment for each case.

Effects of Obesity and Obesity-Related Molecules on Canine Mammary Gland Tumors

Obesity can affect the clinical course of a number of diseases, including breast cancer in women and mammary gland tumors in female dogs, via the secretion of various cytokines and hormones. The objective of this study was to examine the expression patterns of obesity-related molecules such as aromatase, leptin, and insulin-like growth factor 1 receptor (IGF-1 R) in canine mammary carcinomas (CMCs) on the basis of the body condition score (BCS). Comparative analyses of the expression of these molecules, together with prognostic factors for CMCs, including hormone receptors (HRs; estrogen and progesterone receptors), lymphatic invasion, central necrosis of the tumor, and histologic grade, were performed on 56 CMCs. The mean age of CMC onset was lower in the overweight or obese group (8.7 ± 1.9 years) than in the lean or ideal body weight group (10.4 ± 2.7 years). The proportion of poorly differentiated (grade III) tumors was significantly higher in the overweight or obese female dogs. Aromatase expression was significantly higher in the overweight or obese group and was correlated with the expression of HRs (P = .025). These findings suggest that overweight or obese status might affect the development and behavior of CMCs by tumor-adipocyte interactions and increased HR-related tumor growth.

Obesity, expression of adipocytokines, and macrophage infiltration in canine mammary tumors

Obesity influences the development, progression and prognosis of human breast cancer and canine mammary cancer (MC) but the precise underlying mechanism is not well-documented in the fields of either human or veterinary oncology. In the present study, the expression of major adipocytokines, including leptin, adiponectin, and leptin receptor (ObR) in benign (n = 28) and malignant (n = 70) canine mammary tumors was investigated by immunohistochemistry and on the basis of the subjects body condition score (BCS). To evaluate the relationship between obesity and chronic inflammation of the mammary gland, macrophages infiltrating within and around tumoral areas were counted. The mean age of MC development was lower in overweight or obese dogs (9.0 ± 1.8 years) than in lean dogs or optimal bodyweight (10.2 ± 2.9 years), and the evidence of lymphatic invasion of carcinoma cells was found more frequently in overweight or obese group than in lean or optimal groups. Decreased adiponectin expression and increased macrophage numbers in overweight or obese subjects were significantly correlated with factors related to a poor prognosis, such as high histological grade and lymphatic invasion. Leptin expression was correlated with progesterone receptor status, and ObR expression was correlated with estrogen receptor status of MCs, regardless of BCS. Macrophage infiltration within and around the tumor may play an important role in tumor progression and metastasis in obese female dogs and may represent a prognostic factor for canine MCs.

CD44+/CD24– Cancer Stem Cells Are Associated With Higher Grade of Canine Mammary Carcinomas

The CD44+/CD24– phenotype identifies cancer stem cell (CSC) properties in canine mammary carcinoma (MC); however, the histopathological features associated with this phenotype remain to be elucidated. Here, we determined whether the CD44+/CD24– phenotype was associated with hormonal receptor (HR; estrogen receptor [ER] and/or progesterone receptor [PR]) status and/or triple (ER, PR, and human epithelial growth factor receptor 2)–negative (TN) subtype; conventional histological evaluation was also performed. We found that, as single markers, both CD44+ and CD24+ were associated with less aggressive histological types, low grade, and a non-TN subtype; both markers were associated with HR positivity. On the other hand, a CD44+/CD24– phenotype was associated with higher grade of carcinoma. Therefore, our results suggest that immunohistochemical phenotyping for CD44/CD24 is useful for the evaluation of tumor behavior as well as CSC-like properties in canine MCs.

Canine model of ischemic stroke with permanent middle cerebral artery occlusion: clinical features, magnetic resonance imaging, histopathology, and immunohistochemistry.

The purpose of this study was to identify time-related changes in clinical, MRI, histopathologic, and immunohistochemical findings associated with ischemic stroke in dogs. Additionally, the association of cerebrospinal fluid (CSF) and tissue levels of interleukin (IL)-6 with clinical prognosis was assessed. Ischemic stroke was induced by permanent middle cerebral artery occlusion (MCAO) in nine healthy experimental dogs. The dogs were divided into three groups according to survival time and duration of the experimental period: group A (survived only 1 day), group B (1-week experimental period), and group C (2-week experimental period). Neurologic status was evaluated daily. Magnetic resonance imaging (MRI) was performed according to a predetermined schedule. Concentration of IL-6 in CSF was measured serially after ischemic stroke. Postmortem examination was performed for all experimental dogs. During histopathological examination, variable degrees of cavitation and necrosis due to neuronal cytopathic effects, such as pyknotic nuclei and cytoplasmic shrinkage, were observed on the affected side of the cerebral cortex in all dogs. Immunohistochemistry specific for IL-6 showed increased expression in the ischemic lesions. CSF IL-6 concentrations and ischemic lesion volumes 1 day after ischemic stroke were significantly higher in group A compared to groups B and C.

Analysis of Hypoxia-Inducible Factor-1α Expression Relative to Other Key Factors in Malignant Canine Mammary Tumours.

Hypoxia-inducible factor (HIF)-1α plays important physiological roles, but is also of significance in carcinogenesis in man and animals. This study aimed to identify HIF-1α expression in malignant canine mammary tumours (CMTs) and to find correlations with other key factors by using immunohistochemistry (IHC). The histological classification, grading and evaluation of lymphatic invasion were achieved by examining sections stained by haematoxylin and eosin. Determination of molecular subtype, expression of HIF-1α, oestrogen receptor (OR), progesterone receptor (PR), human epidermal growth factor receptor (HER)-2, Ki67, vascular endothelial growth factor (VEGF) and E-cadherin was evaluated by IHC in 87 samples of malignant CMTs. HIF-1α expression correlated significantly with histological type, grade of cancer, negativity for OR and expression of Ki67 and VEGF. Lymphatic invasion, molecular subtype, PR, HER-2 and E-cadherin levels did not significantly correlate with HIF-1α expression. The results of this study imply that HIF-1α may potentially play a role in increased malignancy of CMTs, as it does in human breast cancer.

Evaluation of Clinicopathological Characteristics and Oestrogen Receptor Gene Expression in Oestrogen Receptor-negative, Progesterone Receptor-positive Canine Mammary Carcinomas

The existence of the oestrogen receptor-negative (OR(-))/progesterone receptor-positive (PR(+)) phenotype in canine mammary carcinomas (CMCs) is not well understood, although this phenotype was reported consistently in previous studies. In the present study, immunohistochemistry (IHC) was performed to categorize CMCs with the OR(-)/PR(+) phenotype and compare their clinicopathological features with OR(+)/PR(+) tumours. Of a total of 305 CMCs, 36 (11.8%) were categorized as OR(-)/PR(+) and showed intermediate characteristics between those of OR(+)/PR(+) and OR(-)/PR(-) cases. OR mRNA levels were measured in formalin-fixed, paraffin wax-embedded samples using a novel branched-chain DNA assay method. Similar to the IHC result, one-way analysis of variance showed that the mean normalized OR mRNA level of OR(-)/PR(+) tumours (11.4 ± 16.34) was between that of the OR(-)/PR(-) (mean 4.7 ± 6.35) and OR(+)/PR(+) (mean 15.8 ± 11.95) (P = 0.033) tumours. Only three of the 36 OR(-)/PR(+) tumours completely lacked OR mRNA expression. The OR(-)/PR(+) tumours were not categorized as an independent group nor were they included in the other groups on post-hoc analysis. OR(-)/PR(+) tumours were associated with factors related to poor prognosis compared with OR(+)/PR(+) tumours, but OR(-)/PR(-) tumours were associated with the worst prognostic indicators. Further studies are required in order to determine the clinical significance of the OR(-)/PR(+) phenotype.

CD204-Expressing Tumor-Associated Macrophages Are Associated With Malignant, High-Grade, and Hormone Receptor–Negative Canine Mammary Gland Tumors:

Tumor-associated macrophages (TAMs) are an important component of leukocyte infiltration in tumors. TAMs can be classified into M1 and M2 phenotypes. In the present study, the expression of CD204, an M2-polarized macrophage receptor, was investigated by immunohistochemistry in the area surrounding TAMs in 101 cases of canine mammary gland tumor (CMT). We examined the relationship between M2-polarized TAMs and malignancy, histological subtype, histological grade, molecular subtype, hormone receptor (HR) status, and clinical obesity indices. The mean number of CD204-positive macrophages was significantly higher in malignant CMTs than in benign CMTs (P = .000). The number of CD204-positive macrophages differed significantly between histological grades (P = .000) and were significantly higher in grade III than in grades I and II. Moreover, the mean number of CD204-positive macrophages was significantly higher in HR-negative malignant CMTs than in HR-positive malignant CMTs (P = .035) and in malignant CMTs with lymphatic invasion compared to malignant CMTs without lymphatic invasion (P = .000). These findings suggest that CD204-positive macrophages might affect the development and behavior of CMTs and highlight the potential of CD204 as a prognostic factor.

Increased p63 expression in canine perianal gland tumours

Abstract Introduction p63 is a homologous molecule of p53 and was recently identified as playing important roles in several key cellular processes, including epithelial development and proliferation. Since then, several studies have demonstrated altered p63 expression in various cancers of epithelial origin. Canine perianal gland tumour is one of the most common skin neoplasms in dogs; however, the molecular characteristics of this tumour remain poorly understood. The objective of the present study was to analyse and compare the expression of p63 in canine perianal gland adenomas and carcinomas. Material and Methods Haematoxylin and eosin-stained slides were examined and immunohistochemistry was conducted for a total of 65 samples. Immunohistochemical data for p63 expressions were compared between groups using the Mann-Whitney U test. Results The p63 expression level was increased in perianal gland carcinomas compared to that in the adenoma samples (P < 0.0001). The percentage of cells expressing p63 was higher in perianal gland carcinomas than in adenomas, although the intensity of immunostaining did not differ significantly between the two groups. Conclusion p63 is a candidate factor contributing to the malignant transformation and progression of canine perianal gland tumours.

Expression of Oestrogen Receptor, Progesterone Receptor and Akt in Canine Circumanal Gland Tumours

We investigated the expression of oestrogen receptor alpha (OR-α), progesterone receptor (PR) and Akt in canine circumanal gland tumours. Immunohistochemistry was conducted on seven normal circumanal glands, 30 circumanal gland adenomas and 40 circumanal gland carcinomas. The expression of OR-α and PR was significantly lower in circumanal gland carcinomas than in circumanal gland adenomas. In contrast, the expression of Akt was markedly higher in circumanal gland carcinomas than in circumanal gland adenomas. These results indicate that the progression of canine circumanal gland tumours is influenced by changes in the expression levels of OR-α, PR and Akt. Identifying the molecular mechanisms of canine circumanal gland tumours requires further study.