[Coexpression of keratin and vimentin in squamous cell carcinoma as evidence of pseudosarcomatous differentiation].
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Biomedical subjects
Publications and source records attributed to M Altmannsberger.
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Classification of tumors is based on histogenesis and on determination of malignancy. In well differentiated neoplasias the tumor tissue reveals a similar morphological pattern similar to that of the normal tissue from which they have originated. In contrast less differentiated neoplasias do not show such similarities to normal tissue in conventional stains and special procedures such as electron microscopy or immunohistology have to be performed in order to detect cell specific products. In many undifferentiated tumors this is not possible because loss of differentiation and organisation in tumor cells do not allow the production of cell specific substances. A new possibility for determining the histogenesis of tumors is the use of antibodies which are specific for one type of intermediate filaments. Intermediate filaments are structures, which together with microtubules and microfilaments form the cytoskeleton. Intermediate filaments are composed of different polypeptides, which show a cell type specificity. Keratins are the intermediate filaments characteristically found in keratinizing and nonkeratinizing epithelia. Desmin is the specific intermediate filament type of sarcomeric, visceral and some type of vascular smooth muscle tissue. Vimentin filaments are characteristic of endothelial cells, fibroblasts, macrophages, chondrocytes and most but not all lymphatic cells and the only intermediate filament type present in these cells. Neurofilaments are composed of three different polypeptides, which form the so called neurofilament triplet and are characteristically found in central and peripheral neurons. Glial fibrillary acidic protein (GFAP) forms the intermediate filament system of normal and reactive astrocytes and also some ependymal cells contain GFAP. Thus cells and tissues can be divided into five different types by the use of appropriate polyclonal or monoclonal antibodies. In the current study we were interested to determine with a large number of specimens, whether primary tumors or metastases continue to express the intermediate type characteristic of the normal tissue. The following results demonstrate, there is abundant evidence that intermediate filaments can be used as cell type specific markers both for normal tissue and for tumors. 1. To exclude wrong negative results by intermediate filament typing, a reliable detection of intermediate filaments should be performed on cryostat sections or on material, which has been recently ethanol fixed and paraffin embedded. With many antibodies fixation of the tissue in formalin results in a decrease of reactivity.(ABSTRACT TRUNCATED AT 400 WORDS)
Neurinomas of the hypoglossal nerve are rarely reported. In most cases these tumors are intracranial or sited at the skull base. Only a few solitary neurinomas of the twelfth cranial nerve have been reported. In most of these cases the tumors arose from the descending part of the nerve in the parapharyngeal space. We report the first neurinoma recorded arising from the submandibular course of the hypoglossal nerve.
Cytological specimens of thyroid carcinomas and follicular adenomas obtained by fine-needle aspiration biopsies or touch imprints were investigated with antibodies to keratin, vimentin, and neurofilaments. All tumors were keratin positive. In follicular adenomas as well as in papillary thyroid carcinomas, a coexpression of keratin and vimentin was detected; in follicular carcinomas, only some tumors showed coexpression of keratin and vimentin; and in medullary thyroid carcinomas, positive staining of all six tumors studied was seen with the keratin and neurofilament antibodies, with some tumors also showing coexpression of vimentin. The mechanisms of such coexpression is unclear.
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We analyzed actin expression in two human rhabdomyosarcomas as well as in three rhabdomyosarcomas induced in rats by the injection of nickel sulfide. All five tumors exhibited appreciable amounts of the sarcomeric alpha-actin types, in line with their myogenic differentiation. The level of these actins was particularly high in the rat tumors, which according to morphological criteria, all showed a higher degree of differentiation than the human tumors. Interestingly, in both human tumors and in two of the three rat tumors, the level of the cardiac alpha-actin type was significantly higher than that of adult skeletal muscle alpha-actin. Taken together with the results of recent reports indicating that the cardiac alpha-actin type is a marker of embryonic and fetal skeletal muscle, our findings indicate that rhabdomyosarcomas express the embryonic sarcomeric actin isoform.
Five monoclonal antibodies recognizing different keratin polypeptides in immunoblotting or different epithelial cell types in complex tissues were studied for their suitability as reagents for the differential diagnosis of primary and secondary malignant epithelial liver tumors. The broad specificity keratin antibodies lu-5 and KL-1 stained all epithelial liver neoplasms. In contrast the antibodies CK-7 (Ker-7-specific), CK-2 (Ker-18-specific) and KA-4 (Ker-19-specific in liver) allow these neoplasms to be divided into three groups: Hepatocellular carcinomas were CK-2-positive and CK-7-negative. Cholangiocellular carcinomas, liver metastases of extrahepatic bile duct carcinomas, liver metastases of a ductal carcinoma of breast, and a follicular thyroid carcinoma were stained positively by CK-2, CK-7, and KA-4. In 1 of 6 hepatocellular carcinomas neoplastic hepatocytes were focally labeled by KA-4. In a focal nodular hyperplasia of the liver modified hepatocytes were decorated not only by CK-2 but also by CK-7 and KA-4. Liver metastases of colorectal adenocarcinomas and of a carcinoid tumor were stained positively by CK-2 and KA-4 but not by CK-7.
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A carcinosarcoma of the larynx was analysed by means of a light microscope and by immunohistological staining technique using antibodies against various intermediate filament proteins. Whereas tumour areas of an epithelial character reacted with antibodies against keratin, the spindle cells demonstrated a positive immunofluorescence with vimentin antibodies. Inside some tumour cells a coexpression of keratin and vimentin (intermediate filaments of mesenchymal cells) could be demonstrated. It is likely that these double stained cells represent the primitive stem cell of the carcinosarcoma, differentiating during further development either into epithelial or mesenchymal tumour cells.
Monoclonal antibodies which recognize one or only a few keratin polypeptides have been used to study the distribution of different keratins in benign and malignant breast lesions by immunocytochemical methods. Seven monoclonal antibodies which recognized either different keratin polypeptides by immunoblotting techniques, or identified different epithelial cell types in complex tissues were used. In two mastopathies and three fibroadenomas the antibody lu5 stained luminal cells as well as myoepithelial cells. In contrast the antibodies CK7, Troma 1, CK2 and KA4 labeled only luminal cells, whereas antibody CKB1 decorated only myoepithelial cells. All 15 ductal carcinomas showed a uniform staining of tumor cells with the antibodies Troma 1, CK2, KA4 and lu5. The antibody CK7 also stained all ductal carcinomas, but in two specimens the staining was heterogeneous. The antibody CKB1 decorated only the pre-existing myoepithelial cells in 11 of 12 ductal carcinomas but in the remaining specimen the tumor cells were also strongly positive. Tumor cells in lobular carcinomas were labeled by antibodies CK7, Troma 1, CK2, KA4, bu not by CKB1. The antibody CKS1 showed no staining of any of the benign and malignant breast lesions.
The diagnostic intracytoplasmic perinuclear inclusion bodies within the fibroblastic tumor cells of recurring digital fibrous tumor of childhood (Reye tumor) were found to be ultrastructurally composed of condensed microfilaments that were continuous with axially oriented cytoplasmic filament bundles running toward the cell membrane. Immunofluorescence microscopy performed with antibodies raised against vimentin and against actin revealed a strong positive reaction for vimentin in the tumor cell cytoplasm, whereas the spherical inclusion bodies were actin-positive. From these results the following conclusions may be drawn: (I) the mesenchymal origin of the Reye tumor cells is consistent with the identification of vimentin intermediate filaments and (II) the actin-positive spherical inclusion bodies appear to represent pathological aggregations of microfilaments.
N-Nitrosopiperidine (CAS: 100-75-4) and 2,6-dimethylnitrosomorpholine induced tumors of the olfactory epithelium in white Wistar rats. Some tumors were serially transplanted to NMRI nude mice (nu/nu) and passaged up to 16 times in a 1-year period. Tumor tissues from rats and mice were analyzed by conventional pathological stains, by electron microscopy, and by immunofluorescence microscopy with the use of antibodies specific for different intermediate filaments. Both carcinogens induced tumors built of undifferentiated small, round cells in which neuroblastic (Homer-Wright) rosettes and ependymal (Flexner) rosettes were visible. In some tumors areas of squamous cell metaplasia could be observed, which sometimes differentiated toward squamous cell carcinoma. Electron microscopy showed neurosecretory granules in some tumor cells, and biochemical studies of plasma showed in some instances elevated ACTH and calcitonin levels. Intermediate filament typing showed that in general the undifferentiated tumor cells lack intermediate filaments, although in 6 of 29 tumors a few cells that stained positively for neurofilaments were found. Flexner rosettes, the areas showing squamous cell differentiation, and occasional single tumor cells were positive with keratin antibodies. Neurofilament expression was observed in a minor population of tumor cells placed in tissue culture. These findings are used to argue that the chemically induced rat tumors are a model for human esthesioneuroepithelioma and furthermore that the light basal cells of the epithelium may be the stem cells of the rat tumors as well as of its rare counterparts in humans.
Monoclonal antibodies which recognize particular keratin polypeptides have been used to analyze normal human tissues including pancreas, stomach, colon, gall bladder, and liver as well as tumors of the gastrointestinal tract by immunohistological techniques. Broad specificity (lu5), ker 8 (Troma 1) and ker 18 (CK2) antibodies were positive while a ker 14 specific antibody (CKB1) was negative on all specimens tested. Differential staining patterns were seen with a ker 7 (CK7) and a ker 19 (KA4) antibody. Both antibodies stained gall bladder epithelium, pancreatic ducts but not acinar cells, as well as pancreatic ductal adenocarcinomas. KA4 but not the CK7 antibody stained adenocarcinomas of the stomach and large bowel. Both antibodies stained bile ducts and cholangiocellular carcinoma of the liver but did not stain hepatocytes or hepatocellular carcinomas. The results with keratin monoclonal antibodies compare well with those obtained by others using two dimensional gel electrophoresis and they further support the idea that monoclonal antibodies specific for particular keratin polypeptides will find applications in routine pathological diagnosis.
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There is abundant evidence that intermediate filaments can be used as cell type specific markers both for normal tissue and for tumors. The results of intermediate filament typing in soft tissue tumors and its diagnostic relevance is shown. This system can also be used to solve other problems in surgical pathology. One of the most useful applications of intermediate filament typing is to differentiate the round cell tumors of children; thus, rhabdomyo-sarcomas are desmin positive, malignant lymphomas contain only vimentin, and neuroblastomas show positivity for neurofilaments.