Accurate (DEU10, 4B4B2, 33), American Research Products/Research Diagnostics (DEU10), Biodesign (33), Biogenesis (BIO-41H), Boehringer (DEB5), Dako (DER-11, D33), Eurodiagnostica (D9), EY Labs, Immunotech (D33, HHF35), Shandon Lipshaw (D33), Sigma (DEU10) and Zymed (ZSD1).
Fixation/Preparation
Most of the available antibodies are immunoreactive in paraffin sections and are enhanced by HIER (Pollock et al, 1995). Enzyme digestion is not required if HIER is employed. Clone D33 can be used without enzyme predigestion.
Background
Desmin belongs to the class of "intermediate" (10 nm) filaments and is a cytoplasmic protein, which is characteristically found in myogenic cells. It has a molecular weight of 53 kD and is composed of an N-terminal "headpiece" and a C-terminal "tailpiece", both of which are non-helical in conformation. The two pieces bracket an a-helical middle domain of about 300 amino acid residues which is highly conserved from species to species, with striking interspecies homology. This homology is even more than that exhibited between intermediate filament proteins in the same species, with cytokeratin, vimentin, glial fibrillary acidic protein, neurofilaments and desmin exhibiting sequence homology of about 30% (Nagai et al, 1985; Li et al, 1993).
In smooth muscle cells, desmin is associated with cytoplasmic dense bodies and subplasmalemmal dense plaques and in striated muscle it is linked to sarcomeric Z disks. Muscle cells depleted of desmin (skeletin) are still able to contract in response to adenosine triphosphate and calcium suggesting that desmin played no role in contractility but rather serves to maintain the relationship and orientation of actin and myosin filaments and to anchor them to the plasmalemmal. More recent findings suggest that, like other intermediate filaments of non-epithelial cells, desmin also serves a nucleic acid-binding function, is susceptible to processing by calcium-activated proteases and is a substrate for cyclic adenosine monophosphate-dependent protein kinases. With its shared structural homology to lamins, the proteins of the nuclear envelope, desmin may also serve as a modulator between extracellular influences governing calcium flux into the cell and may have a role in nuclear transcription and translation. These newer roles of the intermediate filaments, including desmin, relegate the supportive cytoskeletal function of intermediate filaments to a secondary role (Goldman et al, 1985).
Applications
The development of sensitive and specific antibodies to the intermediate filaments, including desmin, heralded a new era in diagnostic immunohistochemistry as they allow the subtyping of many seemingly undifferentiated and pleomorphic tumors through intermediate filament analysis. Through the application of judiciously selected panels of antibodies directed to the differential diagnoses derived from the histologic and clinical findings, it is possible to separate the different entities in the diagnostic categories of pleomorphic spindle cell tumors and round cell tumors (Leong et al, 1989). The former group includes rhabdomyosarcoma, leiomyosarcomas and tumors with focal myogenic differentiation such as Triton tumors and malignant mixed MUlerian tumors. The latter group includes embryonal rhabdomyosarcoma, epithelioid leiomyoma and leiomyosarcoma and focal myogenic differentiation in small round cell tumors such as desmoplastic small round cell tumors and primitive/peripheral neuroepithelial tumors. All of these tumors may express desmin (Azumi et al, 1988; Leong & Wannatkrairot, 1992; Parham et al, 1992). In this context, it is important to remember that although myogenous cells often express desmin, it is also seen in myofibroblasts. Focal staining for desmin will be observed in tumors of myofibroblastic differentiation such as the fibromatosis, dermatofibrosarcoma protuberans (Leong et al, 1997) and in reactive conditions with abundant myofibroblasts such as inflammatory pseudotumor and postoperative spindle cell nodule (Hojo et al, 1995). Equally important is the observation that not all muscle cells contain desmin. For example, among mammalian vascular smooth muscle, three immunophenotypes have been observed. Those that display vimentin only, those coexpressing vimentin and desmin and a third group which expresses desmin only (Coindre et al, 1988). Focal staining for desmin may also be seen in tumors with a background of reactive myofibroblasts or with focal myofibroblastic differentiation such as malignant fibrous histiocytoma.
Comments
While initial antibodies to desmin lacked sensitivity and specificity, current commercial antibodies are more reliable. Both monoclonal and polyclonal antibodies are useful but as desmin shares some common epitopes with actin and myosin, it should be ensured that the antibody employed does not show crossreactivity. We employ clones DE-R-11 and D33, both antibodies being enhanced by HIER.
References
•Azumi N, Ben-Ezra J, Battifora H 1988. Immunophenotypic diagnosis of leiomyosarcomas and rhabdomyosarcomas with monoclonal antibodies to muscle-specific actin and desmin in formalin-fixed tissue. Modern Pathology 1: 469-474.
•Coindre J-M, De Mascarel A, Trojani M, De Mascarel I 1988 Immunohistochemical study of rhabdomyosarcoma. Unexpected staining with S-100 protein and cytokeratin. Journal of Pathology 155: 127-132.
•Goldman R, Goldman AE, Green K et al 1985. Intermediate filaments: possible functions as cytoskeletal connecting links between the nucleus and the cell surface. Annals of the New York Academy of Sciences 455: 1-17.
•Hojo H, Newton WA, Hamoudi AB et al 1995 Pseudosarcomatous myofibroblastic tumor of the urinary bladder in children. American Journal of Surgical Pathology 19: 1224-1236.
•Leong AS-Y, Wannatrairot P 1992.A retrospective analysis of immunohistochemical staining in identification of poorly differentiated round cell and spindle cell tumors - results, reagents and costs. Pathology 24: 254-260.
•Leong AS-Y, Kan A, Milios J 1989 Immunohistochemical analysis of malignant round cell tumors in childhood. Surgical Pathology 2: 5-17.
•Leong AS-Y, Wick MR, Swanson PE 1997. Immunohistology and electron microscopy of anaplastic and pleomorphic tumors. Cambridge: Cambridge University Press, pp 59-93, 161-169.
•Li Z, Colucci E, Babinet C, Paulin D 1993 The human desmin gene: a specific regulatory program in skeletal muscle both in vitro and in transgenic mice. Neuromuscular Disorders 3: 423-427.
•Nagai J, Capetanaki YG, Lazarides E 1985 Expression of the genes coding for the intermediate filament proteins vimentin and desmin. Annals of the New York Academy of Sciences 455: 144-155.
•Parham DM, Dias P, Kelly DR, et al 1992. Desmin positivity in primitive neuroectodermal tumors of childhood. American Journal of Surgical Pathology 16: 483-492. childhood. American Journal of Surgical Pathology 16: 483-492.
•Pollock L, Rampling D, Greenwald SE, Malone M 1995. Desmin expression in rhabdomyosarcoma: influence of the desmin clone and immunohistochemical method. Journal of Clinical Pathology 48: 535-538
Bibliografía
Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.
Fixation/Preparation
Most of the available antibodies are immunoreactive in paraffin sections and are enhanced by HIER (Pollock et al, 1995). Enzyme digestion is not required if HIER is employed. Clone D33 can be used without enzyme predigestion.
Background
Desmin belongs to the class of "intermediate" (10 nm) filaments and is a cytoplasmic protein, which is characteristically found in myogenic cells. It has a molecular weight of 53 kD and is composed of an N-terminal "headpiece" and a C-terminal "tailpiece", both of which are non-helical in conformation. The two pieces bracket an a-helical middle domain of about 300 amino acid residues which is highly conserved from species to species, with striking interspecies homology. This homology is even more than that exhibited between intermediate filament proteins in the same species, with cytokeratin, vimentin, glial fibrillary acidic protein, neurofilaments and desmin exhibiting sequence homology of about 30% (Nagai et al, 1985; Li et al, 1993).
In smooth muscle cells, desmin is associated with cytoplasmic dense bodies and subplasmalemmal dense plaques and in striated muscle it is linked to sarcomeric Z disks. Muscle cells depleted of desmin (skeletin) are still able to contract in response to adenosine triphosphate and calcium suggesting that desmin played no role in contractility but rather serves to maintain the relationship and orientation of actin and myosin filaments and to anchor them to the plasmalemmal. More recent findings suggest that, like other intermediate filaments of non-epithelial cells, desmin also serves a nucleic acid-binding function, is susceptible to processing by calcium-activated proteases and is a substrate for cyclic adenosine monophosphate-dependent protein kinases. With its shared structural homology to lamins, the proteins of the nuclear envelope, desmin may also serve as a modulator between extracellular influences governing calcium flux into the cell and may have a role in nuclear transcription and translation. These newer roles of the intermediate filaments, including desmin, relegate the supportive cytoskeletal function of intermediate filaments to a secondary role (Goldman et al, 1985).
Applications
The development of sensitive and specific antibodies to the intermediate filaments, including desmin, heralded a new era in diagnostic immunohistochemistry as they allow the subtyping of many seemingly undifferentiated and pleomorphic tumors through intermediate filament analysis. Through the application of judiciously selected panels of antibodies directed to the differential diagnoses derived from the histologic and clinical findings, it is possible to separate the different entities in the diagnostic categories of pleomorphic spindle cell tumors and round cell tumors (Leong et al, 1989). The former group includes rhabdomyosarcoma, leiomyosarcomas and tumors with focal myogenic differentiation such as Triton tumors and malignant mixed MUlerian tumors. The latter group includes embryonal rhabdomyosarcoma, epithelioid leiomyoma and leiomyosarcoma and focal myogenic differentiation in small round cell tumors such as desmoplastic small round cell tumors and primitive/peripheral neuroepithelial tumors. All of these tumors may express desmin (Azumi et al, 1988; Leong & Wannatkrairot, 1992; Parham et al, 1992). In this context, it is important to remember that although myogenous cells often express desmin, it is also seen in myofibroblasts. Focal staining for desmin will be observed in tumors of myofibroblastic differentiation such as the fibromatosis, dermatofibrosarcoma protuberans (Leong et al, 1997) and in reactive conditions with abundant myofibroblasts such as inflammatory pseudotumor and postoperative spindle cell nodule (Hojo et al, 1995). Equally important is the observation that not all muscle cells contain desmin. For example, among mammalian vascular smooth muscle, three immunophenotypes have been observed. Those that display vimentin only, those coexpressing vimentin and desmin and a third group which expresses desmin only (Coindre et al, 1988). Focal staining for desmin may also be seen in tumors with a background of reactive myofibroblasts or with focal myofibroblastic differentiation such as malignant fibrous histiocytoma.
Comments
While initial antibodies to desmin lacked sensitivity and specificity, current commercial antibodies are more reliable. Both monoclonal and polyclonal antibodies are useful but as desmin shares some common epitopes with actin and myosin, it should be ensured that the antibody employed does not show crossreactivity. We employ clones DE-R-11 and D33, both antibodies being enhanced by HIER.
References
•Azumi N, Ben-Ezra J, Battifora H 1988. Immunophenotypic diagnosis of leiomyosarcomas and rhabdomyosarcomas with monoclonal antibodies to muscle-specific actin and desmin in formalin-fixed tissue. Modern Pathology 1: 469-474.
•Coindre J-M, De Mascarel A, Trojani M, De Mascarel I 1988 Immunohistochemical study of rhabdomyosarcoma. Unexpected staining with S-100 protein and cytokeratin. Journal of Pathology 155: 127-132.
•Goldman R, Goldman AE, Green K et al 1985. Intermediate filaments: possible functions as cytoskeletal connecting links between the nucleus and the cell surface. Annals of the New York Academy of Sciences 455: 1-17.
•Hojo H, Newton WA, Hamoudi AB et al 1995 Pseudosarcomatous myofibroblastic tumor of the urinary bladder in children. American Journal of Surgical Pathology 19: 1224-1236.
•Leong AS-Y, Wannatrairot P 1992.A retrospective analysis of immunohistochemical staining in identification of poorly differentiated round cell and spindle cell tumors - results, reagents and costs. Pathology 24: 254-260.
•Leong AS-Y, Kan A, Milios J 1989 Immunohistochemical analysis of malignant round cell tumors in childhood. Surgical Pathology 2: 5-17.
•Leong AS-Y, Wick MR, Swanson PE 1997. Immunohistology and electron microscopy of anaplastic and pleomorphic tumors. Cambridge: Cambridge University Press, pp 59-93, 161-169.
•Li Z, Colucci E, Babinet C, Paulin D 1993 The human desmin gene: a specific regulatory program in skeletal muscle both in vitro and in transgenic mice. Neuromuscular Disorders 3: 423-427.
•Nagai J, Capetanaki YG, Lazarides E 1985 Expression of the genes coding for the intermediate filament proteins vimentin and desmin. Annals of the New York Academy of Sciences 455: 144-155.
•Parham DM, Dias P, Kelly DR, et al 1992. Desmin positivity in primitive neuroectodermal tumors of childhood. American Journal of Surgical Pathology 16: 483-492. childhood. American Journal of Surgical Pathology 16: 483-492.
•Pollock L, Rampling D, Greenwald SE, Malone M 1995. Desmin expression in rhabdomyosarcoma: influence of the desmin clone and immunohistochemical method. Journal of Clinical Pathology 48: 535-538
Bibliografía
Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.
