Immunohistochemical profile of myogenin and MyoD1 does not support skeletal muscle lineage in alveolar soft part sarcoma.
BACKGROUND
The histogenesis of alveolar soft part sarcoma remains elusive. Myogenic origin is favored, although conflicting data on immunohistochemical demonstration of muscle-associated markers exist. Myogenin and MyoD1, transcription factors of the myogenic determination family, have crucial roles in commitment and differentiation of mesenchymal progenitor cells to myogenic lineage and in maintenance of skeletal muscle phenotype. Their immunohistochemical detection is specific in characterization of rhabdomyosarcoma.


METHODS
Antibodies for myogenin, MyoD1, desmin, and muscle-specific actin were employed on a large series of cases (n = 19) of formalin-fixed, paraffin-embedded alveolar soft part sarcoma.


RESULTS
Minimal scattered nuclear staining was seen with myogenin. All cases had pronounced, nonspecific granular cytoplasmic immunostaining with MyoD1; nuclei were negative. All tumors were negative for desmin and muscle-specific actin. Ultrastructural study in 10 cases failed to reveal features of skeletal muscle differentiation.


CONCLUSIONS
Cytoplasmic staining with MyoD1 in alveolar soft part sarcoma may correspond to cross-reactivity with an undetermined cytoplasmic antigen. The lack of immunostaining with myogenin, MyoD1, desmin, and muscle-specific actin provides evidence against a myogenic origin for alveolar soft part sarcoma.
Gómez
J A
JA
Department of Pathology, Henry Ford Hospital, Detroit, MI 48202-2689, USA.
Amin
M B
MB
Ro
J Y
JY
Linden
M D
MD
Lee
M W
MW
Zarbo
R J
RJ
D000199:Actins / Q000032:analysis; D000328:Adult; D019070:Cell Lineage; D002675:Child, Preschool; D003893:Desmin / Q000032:analysis; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D002479:Inclusion Bodies / Q000648:ultrastructure; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000473:pathology*; D017570:MyoD Protein / Q000032:analysis*; D018008:Myogenin / Q000032:analysis*; D018234:Sarcoma, Alveolar Soft Part / Q000737:chemistry / Q000556:secondary*; D012983:Soft Tissue Neoplasms / Q000737:chemistry / Q000473:pathology*; D015534:Trans-Activators / Q000032:analysis*
D000199:Actins; D003893:Desmin; C503799:MYOG protein, human; D017570:MyoD Protein; C057363:MyoD1 myogenic differentiation protein; D018008:Myogenin; D015534:Trans-Activators