title: The cardiac isoform of alpha-actin in regenerating and atrophic skeletal muscle, myopathies and rhabdomyomatous tumors: an immunohistochemical study using monoclonal antibodies.
abstract: The two sarcomeric isoforms of actins, cardiac and skeletal muscle alpha-actin, are highly homologous so that their immunohistochemical distinction is extremely difficult. Taking advantage of monoclonal antibodies distinguishing the two conservative amino acid exchanges near the aminoterminus, we have performed an extended immunohistochemical analysis of the cardiac alpha-actin (CAA) isoform in normal, regenerating, diseased and neoplastic human muscle tissues. Intense and uniform CAA staining is seen in fetal and adult myocardium and in fetal skeletal muscle while adult skeletal muscle is essentially negative, except for muscle spindle myocytes and a few scattered muscle fibres with overall reduced diameter. By contrast, CAA synthesis is markedly induced in regenerating skeletal muscle cells, in Duchenne muscular dystrophy and upon degenerative atrophy. CAA has also been detected in certain vascular and visceral smooth muscle cells. Among tumors, CAA has consistently been seen in rhabdomyosarcomas and rhabdomyomatous cells of nephroblastomas, whereas, smooth muscle tumors have shown only occasional staining. While the synthesis of this actin isoform is less restricted than previously thought, monoclonal antibodies against CAA provide a well-defined, reliable and sensitive diagnostic tool for the definition and detection of aberrant differentiation in diseased skeletal muscle and of striated muscle differentiation in rhabdomyosarcomas.
authors.affiliation: Institute of Pathology, Philipp University of Marburg, Baldingerstrasse, D-35033 Marburg, Germany. mollr@med.uni-marburg.de
authors.forename: Roland
authors.initials: R
authors.lastname: Moll
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Holzhausen
authors.forename: Hans-Dieter
authors.initials: HD
authors.lastname: Mennel
authors.forename: Caecilia
authors.initials: C
authors.lastname: Kuhn
authors.forename: Renate
authors.initials: R
authors.lastname: Baumann
authors.forename: Christiane
authors.initials: C
authors.lastname: Taege
authors.forename: Werner W
authors.initials: WW
authors.lastname: Franke
mesh_terms: D000199:Actins / Q000032:analysis* / Q000096:biosynthesis; D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology*; D014408:Biomarkers, Tumor; D002454:Cell Differentiation; D005333:Fetus / Q000737:chemistry; D006801:Humans; D007150:Immunohistochemistry; D018482:Muscle, Skeletal / Q000737:chemistry* / Q000473:pathology / Q000502:physiology; D009133:Muscular Atrophy / Q000378:metabolism*; D009135:Muscular Diseases / Q000378:metabolism*; D009206:Myocardium / Q000737:chemistry* / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000737:chemistry; D012038:Regeneration / Q000502:physiology*; D012208:Rhabdomyosarcoma / Q000378:metabolism*
chemical_list: D000199:Actins; D000911:Antibodies, Monoclonal; D014408:Biomarkers, Tumor