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1.
Alkaline phosphatase (ALK-P) reactions at the light and electron microscopic levels were performed on eight canine mammary mixed tumours. In the morphologically normal gland next to the tumours, the myoepithelial cells and the stromal tissues near the acinar basement membranes both showed a positive ALK-P reaction by light microscopy. At the electron microscopic level, those parts of the myoepithelial cell membrane that were in contact with other cells--myoepithelial or lumenal epithelial--showed an ALK-P-positive reaction, as did the adjacent stromal tissue. The characteristic tumour cells, at sites of early proliferation, were ALK-P-positive, while in the mucoid and chondroid areas of the mixed tumours they were largely ALK-P-negative by light microscopy. By electron microscopy, those neoplastic cells which were in contact with other cells typically showed a positive ALK-P reaction, while those cells which were in contact with mucoid or chondroid matrix were largely negative. Although the cytoplasmic filaments of the neoplastic cells were 10 nm thick, and those of normal myoepithelial cells were 6 to 8 nm thick, the observations reported provide further evidence for the view that the essential cells of the canine mammary mixed tumour are derived from myoepithelial cells.  相似文献   

2.
Cytokeratin 5 and p63 have been described as basal and myoepithelial cell markers in human breast. Mixed tumors of the canine mammary gland have been associated with a myoepithelial origin. Cytokeratin 5 expression has not been evaluated in these tumors. We investigated the relation between cytokeratin 5 and p63 double-immunohistochemical expression in 23 mixed tumors of the canine mammary gland (10 benign mixed tumors and 13 carcinomas arising from benign mixed tumors) and their origin. Cytokeratin 5 and p63 co-expression was observed in myoepithelial cells of benign mixed tumors, as well as in squamous differentiation of carcinoma arising from benign mixed tumors. Though a few interstitial spindle cells of the mesenchymal components expressed both p63 and cytokeratin 5, the basal epithelial cells were labeled only by cytokeratin 5. The co-expression of p63 and cytokeratin 5 in myoepithelial cells and squamous differentiation suggest that, like in human breast, cytokeratin 5 can also be considered a myoepithelial- and squamous-cell differentiating marker in canine tumors. The presence of some interstitial spindle cells stained for p63 and cytokeratin 5 might be associated with a myoepithelial origin of the mesenchymal component of mixed tumors of the canine mammary gland. Moreover, contrary to p63, basal epithelial cells were labeled by cytokeratin 5, indicating that cytokeratin 5 may not represent an exclusive myoepithelial cell marker but also a basal epithelial cell marker in canine mixed tumors. According to these data, basal epithelial cells may be related to the origin of the epithelial component of mixed tumors of the canine mammary gland.  相似文献   

3.
The reduction or loss of E-cadherin (E-cad), a calcium-dependent epithelial cell adhesion molecule, has been associated with tumor dedifferentiation and invasiveness. The immunohistochemical pattern of E-cad expression was evaluated in formalin-fixed and paraffin-embedded sections of 6 normal mammary glands, 3 dysplasias, 12 benign tumors (8 benign mixed tumors, 4 adenomas), and 60 malignant tumors (12 stage 0, 29 stage I, 19 stage II) of the canine mammary gland. E-cadherin expression was classified as membranous, when on cell-cell boundaries, or as cytoplasmic, when in the form of a diffuse cytoplasmic staining. In addition, the percentage of E-cad-positive epithelial neoplastic cells was graded by a semiquantitative method, categorizing cases into a reduced (or -) type group, when showing less than 25% positivity, a reduced (or +/-) type group, when showing 25-75% positivity, and a preserved (or +) type group, when more than 75% positive cells were present. In the normal mammary gland, E-cad expression was evident in epithelial luminal cells. A stronger positivity was revealed in ductular than in alveolar luminal cells. The myoepithelial cells showed inconsistent, weak cytoplasmic positivity in the normal gland as well as in mammary tumors. In normal glands and benign and malignant noninvasive tumors, E-cad expression was mainly membranous and preserved in most of the epithelial cells. In stage I tumors, both membranous (38%) and cytoplasmic (62%) positivity were well represented, as well as preserved type (55%) and reduced type (45%) tumors. All stage II malignant tumors showed the highest frequency of cytoplasmic positivity (79%) and reduced type (62%) tumors.  相似文献   

4.
A pleomorphic adenoma of the lacrimal gland in a dog   总被引:1,自引:0,他引:1  
A 13-year-old female mongrel dog had a pleomorphic adenoma of the lacrimal gland in the right upper orbit. The tumor measured 3.8 x 3.0 x 3.3 cm, appeared white, round, and firm, and pressed the right globe and surrounding tissues. Histopathologically, the tumor had a thin connective tissue capsule and was composed of tubules with two cell types, some resembling luminal epithelial cells making up the tubular structures and the other of myoepithelial cells. Epithelial tubules were disposed in an adenomatous fashion and separated from each other by proliferating pleomorphic myoepithelial cells. Immunohistochemically, large numbers of the luminal epithelial cells revealed an immunopositive reaction against keratin/cytokeratin (AE1/AE3), and some epithelial cells reacted against cytokeratin 14. Spindle-shaped myoepithelial cells revealed an immunopositive reaction against cytokeratin 14, alpha-smooth muscle actin, and vimentin. A small number of myoepithelial cells reacted against desmin. S-100 protein immunopositivity was frequently found in luminal epithelial cells and rarely in the pleomorphic myoepithelial cells. Glial fibrillary acidic protein positivity was commonly found in myoepithelial cells, myxoid matrices, and intracystic materials, but not in luminal epithelial cells.  相似文献   

5.
In skeletal muscle cells, myofibrillar proteins are highly organized into sarcomeres in which thick filaments interdigitate with thin filaments to generate contractile force. The size of thick filaments, which consist mainly of myosin molecules, is strictly controlled. However, little is known about the mechanisms by which myosin molecules assemble into thick filaments. Here, we assessed the ability of each domain of myosin heavy chain (Myh) to form thick filaments. We showed that exogenously expressed subfragment 2 (S2) + light meromyosin (LMM) of Myh was efficiently incorporated into thick filaments in muscle cells, although neither solely expressed S2 nor LMM targeted to thick filaments properly. In nonmuscle COS7 cells, S2+LMM formed more enlarged filaments/speckles than LMM. These results suggest that Myh filament formation is induced by S2 accompanying LMM. We further examined the effects of Myh C‐terminus on thick filament assembly. C‐terminal deletion mutants were incorporated not into entire thick filaments but rather into restricted regions of thick filaments. Our findings suggest that the elongation of myosin filaments to form thick filaments is regulated by S2 as well as C‐terminus of LMM.  相似文献   

6.
Nasolabial glands are serous glands forming a thick subcutaneous layer in the bovine muzzle. In order to identify the different epithelial cell types, both immunofluorescent and immunoperoxidase techniques were employed on frozen and fixed sections using monoclonal antibodies to cytoskeletal proteins and S-100. Actin was also detected with phalloidin. The results show that four cell types can be identified on the ground of the different composition of the cytoskeletal filaments: acinar, basket, luminal duct and basal duct cells. Acinar, luminal duct cells and basal duct cells express different patterns of cytokeratins, as shown by the 12 anti-cytokeratin monoclonal antibodies used, and both basket cells and the basal cells of intercalated ducts are also reactive to phalloidin and anti-x-smooth muscle actin monoclonal antibody. The presence of actin supports the conclusion that basal duct cells are also contractile elements, i. e. myoepithelial cells. Vimentin, glial fibrillary acidic protein (GFAP), and S-100, molecules considered to be markers of myoepithelial cells by many AA., were not found. The intermediate filaments of the duct epithelium appear more complex and heterogeneous in comparison with those present in the acinar cells.  相似文献   

7.
Normal and well differentiated neoplastic canine tissues were immunohistochemically stained for keratin, vimentin and desmin intermediate filament proteins using commercially available monoclonal antibodies. Keratin was detected in 56 of 57 carcinomas, vimentin in 59 of 62 sarcomas and desmin in three of four muscle cell tumors. Most normal and neoplastic tissues expressed only one type of intermediate filament; exceptions were one hemangiosarcoma and one pulmonary carcinoma in which there was coexpression of vimentin and keratin proteins. Since immunohistochemical detection of intermediate filaments has tissue-specific distribution in the majority of well differentiated canine neoplasms, these stains may be useful in the differential diagnosis of anaplastic canine tumors. However, the monoclonal antibodies to cytokeratin which were tested in this study failed to detect intermediate filaments in liver, pancreas and salivary glands which suggests that these antibodies may also be unable to detect epithelial tumors derived from these tissues. In addition, in nine neoplasms, the normal tissues adjacent to neoplastic cells failed to stain for the intermediate filament normally expressed. When this occurs, evaluation of intermediate filament expression is invalid for the determination of tissue of origin of the neoplastic cells.  相似文献   

8.
A rare case of complex apocrine carcinoma displaying dominant myoepithelial proliferation developed in the right leg subcutis of a 10-year-old male dog. The major cell population consisted of diffusely proliferating p63-expressing neoplastic cells that were largely myoepithelial in origin co-expressing α-smooth muscle actin. A small portion of the cell population consisted of concomitant basal epithelial cells lacking α-smooth muscle actin expression. The minor population consisted of p63-negative apocrine gland cells that expressed cytokeratin 8. The myoepithelial cell population showed a rather stronger proliferation activity than did the apocrine epithelial population. Thus, this tumor might have been derived from basal epithelial cells characterized by more predominant myoepithelial differentiation than luminal apocrine epithelial differentiation.  相似文献   

9.
Ultrastructure of feline mammary hypertrophy   总被引:1,自引:0,他引:1  
The ultrastructure of feline mammary hypertrophy was studied in a five-month-old female which had aborted recently, a ten-year-old female which was one month postestrus, and a four-year-old progestin-treated neutered male. Morphologic comparisons were made to normal mammary tissue from a one-year-old female cat. Hypertrophied mammary tissue had the same cell types and spatial relationships as did the normal gland. Major differences included a more highly developed duct system composed of metabolically active cells which often were arranged in multiple cell layers, and periductular stroma with increased fibroblasts and vascularization. Hypertrophied epithelial cells were characterized generally by smooth-contoured nuclear membranes, more evenly dispersed heterochromatin, prominent nucleoli, increased polyribosomes, and elongated mitochondria. Secretory activity was developed significantly only in the cat that had aborted recently. Modifications in myoepithelial cells included: more evenly dispersed nuclear heterochromatin, thicker bundles of cytoplasmic filaments, more straight plasma membranes along the basal lamina, and elongated hemidesmosomes. Multilayering of the basal lamina was accentuated. Stromal fibroblasts had nuclear heterochromatin distributed similarly to that of epithelial and myoepithelial cells, and increased rough endoplasmic reticulum. Myoepithelial cells did not contribute to the increased stromal cellularity. No significant ultrastructural differences were noted between mammary hypertrophy in young, old, and progestin-treated cats.  相似文献   

10.
The aim of this study was to evaluate prognostic and/or diagnostic factors of canine mammary tumors by immunohistochemically analyzing the expression of alpha basic crystallin (αB-c). For this, formalin-fixed, paraffin-embedded blocks of 51 naturally-occurring canine mammary tumors (11 benign and 40 malignant) were used. Tissue from eight normal canine mammary glands were served as a control. Immunohistochemically, in the control mammary tissues, a few luminal epithelial cells were αB-c positive but myoepithelial cells were negative. In benign or simple type malignant tumors, αB-c expression was observed in luminal epithelial cells while the myoepithelial basal cells were negative. In benign or complex type malign tumors, positive staining was predominantly found in the cytoplasm of epithelial cells. Immunoreactivity of αB-c was also observed in neoplastic myoepithelial cells. Statistically, the number of cells immunolabeled with αB-c was found to be significantly different among tissues from normal canine mammary glands, benign lesions, and malignant tumors (p < 0.05). αB-c immunoreactivity was higher in malignant tumors than the control mammary tissues (p < 0.001). Data obtained in the current study revealed a strong association between high expression levels of αB-c and primary mammary gland tumors in canines.  相似文献   

11.
Seventy-three mammary tumors and three mammary tissue specimens were examined to elucidate the expression of bone morphogenetic protein (BMP)-6 in the myoepithelial cells of canine mammary gland tumors. Morphologically, the myoepithelial cells were classified into four types: resting and proliferating cells inside the basement membrane, and spindle- and star-shaped cells proliferating in the outer area of the basement membrane. The characteristics of these myoepithelial cells were confirmed by immunohistochemistry using antibodies raised against keratin, cytokeratin 19, alpha-smooth muscle actin, and vimentin. In simple adenoma, a small number of resting myoepithelial cells was immunopositive for BMP-6. In complex adenomas and benign mixed tumors, all types of myoepithelial cells, depending in some cases on their specific location within the tumor, were immunopositive for BMP-6, but almost all of the tubular epithelial cells were immunonegative. Foci consisting of a proliferation of BMP-6-positive star- and spindle-shaped cells had mucinous stroma with marked hyaline and chondroid changes. In contrast, the foci with BMP-6-negative spindle- and star-shaped cells tended to have mucinous stroma without chondroid change. Several types of mesenchymal cells including chondrocytes, osteoblasts, and fibroblastlike cells in the mixed tumors, showed an intense immunopositive reaction for the BMP-6 antibody, and were located close to the ectopic cartilage and bone matrix. No significant immunoreactivity for BMP-6 was observed in most of the malignant mammary tumors; only one malignant mixed tumor was examined. All of these findings indicate that BMP-6 expression in myoepithelial cells may increase in complex adenomas and benign mixed tumors in canine mammary glands, and that BMP-6 expression is most intense in the vicinity of chondroid matrix in these tumors.  相似文献   

12.
Leydig cells of lesser mouse deer (Tragulus javanicus) testes were observed using light and transmission electron microscopies. Sexually mature lesser mouse deer were obtained in East Malaysia. The testes were perfused with 5% glutaraldehyde, postfixed with 1% OsO4, dehydrated in ethanol and embedded in Araldite. The semithin sections were cut, stained with toluidine blue and observed under light microscopy. The ultrathin sections were cut, stained with uranyl acetate and lead citrate, and examined using a JEM-1200 transmission electron microscope. As a result, two types of filament bundles were frequently recognized in Leydig cells, but not in other testicular cells. These bundles were clearly seen at even a light microscopic level. One type was bundles of actin filaments (approximately 5 nm in diameter). These structures were found not only in the cytoplasm but also in the nucleus. The other type was bundles of intermediate filaments (approximately 10 nm in diameter). These structures were found only in the cytoplasm. The existence of filament bundles has never been reported in the testicular cells of another mammalian species. Thus, while bundles of actin and intermediate filaments are specifically present in the Leydig cells of the lesser mouse deer, their functions are still unclear.  相似文献   

13.
A primary culture system of equine uterine epithelial cells was developed to study interactions between these cells in vitro. Cultures were prepared by combined mechanical and collagenase separation of cells from endometrial biopsies taken from mares during estrus and diestrus. Cells were maintained in DME/F12 medium containing 10% fetal bovine serum. The purity of the epithelial cell population was estimated to be greater than 95% based upon the cobblestone morphology of cells and a uniform indirect immunofluorescence labelling of cells with an antibody directed against cytokeratin intermediate filament proteins. Radiating cytoplasmic cytokeratin filaments were characteristic of cells labelled after 3 days in culture. Preliminary analysis of the incidence and rate of cell-to-cell communication between epithelial cell populations was conducted using a fluorescence recovery after photobleaching assay. Recovery of carboxyfluorescein fluorescence in cells which were laser photobleached and in contact with other cells was monitored at one-minute intervals over 5 minutes. The incidence of communication among cells isolated during estrus and diestrus was 100%. The mean rates of fluorescence recovery at one minute (8.25% ± SEM 0.91 and 10.94% ± SEM 1.20 for cells obtained from estrous and diestrous mares, respectively) were not significantly different. These studies indicate that cells isolated from the endometrium of the mare are capable of intercellular diffusion of regulatory and informational molecules between cells in contact.  相似文献   

14.
Myoepitheliomas are subcutaneous tumors that arise from myoepithelial cells of various exocrine glands. In a retrospective study of 142 tumors observed over a period of 3 years, myoepitheliomas occurred spontaneously in A/HeJ, A/J, BALB/cJ, BALB/cByJ, LLC.A/Ckc, and NOD/Lt inbred strains of mice. Tumors presented primarily in the subcutaneous tissues of the ventral neck (74% of the myoepitheliomas evaluated) but were observed in several other subcutaneous locations, including the head, perineum, and ventral abdomen. These areas were adjacent to salivary, mammary, clitoral, preputial, and Harderian glands. Forty myoepitheliomas were tested by the avidin-biotin complex technique with a panel of antisera specific for mouse keratins, intermediate filaments, and other cytoskeletal proteins to determine the cell type from which this neoplasm originated. Antibodies directed against the specific mouse keratins K5, K6, and K14, and a broadly cross-reactive cytokeratin antibody stained acinar and ductal myoepithelial cells in normal mammary, salivary, and Harderian glands, and neoplastic cells in all cases. Antisera directed against a smooth muscle actin (anti-alpha-sm-1) stained acinar myoepithelial cells of the glands and vascular smooth muscle but neither ductular myoepithelial cells nor tumor cells. This supports the notion that these tumors originate from extraglandular ductular myoepithelial cells. Southern blots, prepared from DNA extracted from nine myoepitheliomas, did not show restriction fragment length polymorphisms when mouse mammary tumor virus (MMTV) cDNA or Int-1 genomic DNA probes were used; this implies that a retrovirus is not the etiologic agent.  相似文献   

15.
Several immunohistochemical markers have been used to demonstrate the presence of myoepithelial cells in order to determine their role in the histogenesis of mammary tumors. p63, a recently characterized p53 homologue, is consistently expressed in myoepithelial cells of the human breast; however, no assessment of its immunoreactivity has been reported so far in canine mammary tissues. We investigated p63 immunohistochemical expression, as a novel myoepithelial cell nuclear marker, in 81 samples of normal (n = 2), hyperplastic (n = 11), and neoplastic (n = 68) canine mammary tissues. Myoepithelial phenotype was confirmed by using complementary monoclonal antibodies: alpha-smooth muscle actin, cytokeratin 14, cytokeratin AE1/AE3, and vimentin. p63 expression was observed in 91.4% (74/81) of the samples evaluated. Normal mammary glands, mammary hyperplasias, and benign tumors showed 100% immunoreactivity, with p63 expression restricted to myoepithelial cell nuclei. In general, benign mixed tumors showed a basal cell compartment immunoreactive to p63, with a gradual decrease of its expression during myoepithelial transformation. p63 expression was found in 72% of malignant tumors, allowing myoepithelial or basal cell identification in spindle-cell carcinomas (2/2), tubulopapillary carcinomas (8/9), solid carcinomas (7/10), and carcinosarcomas (1/3). The osteosarcoma analyzed was p63 negative. In our series, stromal components were consistently nonreactive to p63. In conclusion, the present study reveals p63 as a sensitive and highly specific marker of myoepithelial cells in canine mammary tissues, and the authors suggest p63 as an additional marker for defining myoepithelial histogenesis.  相似文献   

16.
Parathyroid hormone-related protein (PTHrP) is produced by the lactating mammary gland and is present in milk in a biologically active form. The goal of this investigation was to determine if cells cultured from the lactating mammary glands of cows would secrete PTHrP in vitro. Mammary acini were isolated from lactating cows at 1–6 wk after calving, and fresh or cryopreserved mammary acini were cultured for 14 d on Type I collagen. Cultures on thick layers of collagen (2.5 mm) were detached and allowed to contract on Day 6. PTHrP production was measured by N-terminal radioimmunoassay and bioassay (increased cAMP levels in ROS 17/2.8 osteoblast-like cells). The mammary cells reached confluence at Day 6. PTHrP production was low at Day 2 (<0.5 ng/ml) but increased to peak production (2–4 ng/ml) at approximately Day 6 and remained constant until Day 14. Immunoreactive and bioactive PTHrP levels in the culture medium correlated well. The cultures produced lactoferrin (2,000–2,300 ng/ml) and αs1-casein (14–19 ng/ml). Prolactin stimulated PTHrP production approximately 50% on Days 6–14. PTHrP production was increased approximately 100% by treatment with epidermal growth factor (10 ng/ml) for 2 d. Morphologic evaluation of cultures on thick, contracted collagen at Day 14 revealed an inner layer of mammary epithelial cells overlying myoepithelial cells and an outer layer of collagen containing stromal cells. Immunohistochemistry demonstrated positive staining for PTHrP and cytokeratin in both mammary epithelial and myoepithelial cells and a-smooth muscle actin in myoepithelial cells. These data demonstrated that cryopreserved mammary tissue from lactating cows could be cultured in vitro and secreted PTHrP in a regulated manner. This in vitro model will be useful to investigate the function and regulation of PTHrP in the lactating mammary gland.  相似文献   

17.
The development of the parotid gland was examined in 36 bovine embryos and foetuses with a crown-rump-length (CRL) from 28 up to 1000 mm by light, transmission electron microscopical and actin-immunohistochemical methods. The anlage of the parotid gland in an embryo with 28 mm CRL can be found at the lateral angle of the primitive oral cavity as a local thickening of the epithelium. During the second month, the differentiation of primary ducts and endbuds starts and a lumen develops in the primary ducts. At the end of the second month a lumen appears in the terminal endbuds. In the immature endpiece cells first secretory granules can be seen from a CRL of 240 mm. In the third month differentiation between intra- and inter-lobular ducts is possible. Immature myoepithelial cells present as a basal layer of flattened cells between the epithelial cells and the basement membrane at the end of the second month. During further development they increase in number, become more flattened and form long cellular processes. At the end of the fourth month isolated actin filament bundles are formed, which were also detected by an antibody against smooth muscle actin. The actin filaments condense continuously until they fill the cell processes completely at the end of foetal development.  相似文献   

18.
Spontaneous basaloid adenomas occurred in four out of 354 dogs with mammary tumors. Affected dogs were pure-bred, intact females between 6 and 8 years of age. Three dogs were nuliparous, two had pseudopregnancies, and none had received contraceptive steroids. The tumors were multiple (three cases) or unique, less than 1 cm in diameter, well delineated, and composed of uniform cords and clusters of monomorphic epithelial cells with focal signs of squamous or glandular differentiation. A basal cell immunophenotype (cytokeratins 5 and 14 positive) without either glandular epithelial (cytokeratins 8, 18, and 19 negative) or myoepithelial (calponin negative) differentiation was observed in the majority of tumor cells. No recurrence or metastasis was recorded after follow-up periods between 3 and 24 months. In spite of the hormone-dependent nature of this tumor in female Beagles given experimental contraceptive steroids, spontaneous basaloid adenomas lacked estrogen receptor alpha and progesterone receptors.  相似文献   

19.
Skeletal muscle consists of bundles of myofibers containing millions of myofibrils, each of which is formed of longitudinally aligned sarcomere structures. Sarcomeres are the minimum contractile unit, which mainly consists of four components: Z‐bands, thin filaments, thick filaments, and connectin/titin. The size and shape of the sarcomere component is strictly controlled. Surprisingly, skeletal muscle cells not only synthesize a series of myofibrillar proteins but also regulate the assembly of those proteins into the sarcomere structures. However, authentic sarcomere structures cannot be reconstituted by combining purified myofibrillar proteins in vitro, therefore there must be an elaborate mechanism ensuring the correct formation of myofibril structure in skeletal muscle cells. This review discusses the role of myosin, a main component of the thick filament, in thick filament formation and the dynamics of myosin in skeletal muscle cells. Changes in the number of myofibrils in myofibers can cause muscle hypertrophy or atrophy. Therefore, it is important to understand the fundamental mechanisms by which myofibers control myofibril formation at the molecular level to develop approaches that effectively enhance muscle growth in animals.  相似文献   

20.
Expression of maspin in mammary gland tumors of the dog   总被引:1,自引:0,他引:1  
Maspin is a serine protease inhibitor that inhibits tumor invasion and metastasis in human breast cancer and is consistently expressed by mammary myoepithelial cells (MECs). To analyze the value of maspin as a marker of the MEC layer of the normal and tumoral canine mammary gland, the immunohistochemical expression of maspin was studied in formalin-fixed tissues from 55 benign and malignant tumors (40 tumors also contained the surrounding normal mammary gland) using a commercially available monoclonal antibody. Periacinar and periductal MECs of all 40 normal mammary glands were stained by the anti-human maspin monoclonal antibody, and immunoreactivity was observed in the nucleus and cytoplasm of these cells. In addition, maspin was found in 53 (98%) of the tumors studied, reacting with the MECs in 100% of benign tumors and 93% of malignant tumors and to the epithelial cells of 16% of benign and 73% of malignant tumors. In the MEC compartment, immunoreactivity was observed in the cytoplasm of hypertrophic MECs, fusiform MECs, stellate MECs, rounded (myoepithelial) cells, and chondroblasts. In the epithelial cell compartment, immunoreactivity was observed in the cytoplasm of cells with and without squamous differentiation. Stromal myofibroblasts were unreactive. Maspin appears to be a very sensitive marker of the normal and neoplastic myoepithelium that, contrary to smooth muscle differentiation markers, does not stain stromal myofibroblasts. In addition, a subset of neoplastic epithelial cells reacted with the maspin antibody. The relationship between maspin expression in different cellular compartments of canine mammary carcinomas and the biologic aggressiveness of the disease remains to be elucidated.  相似文献   

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