Immunohistochemical profile of myogenin and MyoD1 does not support skeletal muscle lineage in alveolar soft part sarcoma.
ABSTRACT 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.
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.
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.
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.
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ABSTRACT: Myogenin belongs to a group of myogenic regulatory proteins whose expression determines commitment and differentiation of primitive mesenchymal cells into skeletal muscle. The expression of myogenin has been demonstrated to be extremely specific for rhabdomyoblastic differentiation, which makes it a useful marker in the differential diagnosis of rhabdomyosarcomas (RMS) from other malignant small round cell tumors of childhood. Commercially available antibodies capable of detecting myogenin in routinely processed formalin-fixed paraffin-embedded (FFPE) tissue are now available. In this study, we evaluated myogenin expression using the monoclonal myf-4 antibody (Novocastra Labs) on FFPE in a large number of pediatric tumors in order to define the clinical utility of this marker. A total of 119 tumors were studied. These included 48 alveolar RMS (ARMS), 20 embryonal RMS (ERMS), one spindle cell RMS, 16 Ewing's sarcomas (ES), six nephroblastomas, two ectomesenchymomas, seven precursor hematopoietic neoplasms, five olfactory neuroblastomas, three neuroblastomas, six desmoplastic small round cell tumors, and five rhabdoid tumors. Distinct nuclear staining for myogenin was noted in all 69 RMS. Notably, the number of positive tumor cells differed between the ARMS and ERMS. In ARMS, the majority of tumor cells (75 to 100%) were positive, in contrast to ERMS, in which the positivity ranged from rare + to 25% in all but three tumors. Additionally, myogenin positivity was seen in two of two ectomesenchymomas and in two nephroblastomas with myogenous differentiation. All other tumors were clearly negative. Our results indicate that staining for myogenin is an extremely reliable and specific marker for rhabdomyoblastic differentiation. It gives consistent and easily interpretable results in routinely fixed tissues.Modern Pathology 10/2000; 13(9):988-93. DOI:10.1038/modpathol.3880179
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ABSTRACT: Alveolar soft part sarcoma (ASPS) is a rare malignant tumor and little is known about its clinical features and management. We report on a series of 19 pediatric patients managed over 20 years. Primary conservative surgery was performed in all patients and was radical in nine, non-radical in three; seven patients underwent biopsy alone (3 unresectable tumors, 4 metastatic disease). In two cases radical surgery was performed after primary chemotherapy. Radiotherapy was delivered to 8 patients, chemotherapy to 15. After a median follow-up of 74 months, the five-year survival was 80% for the whole series, 91% for patients with localized disease, 100% for patients with tumor < or = 5 cm, and 31% for those > 5 cm; 16 of 19 patients were alive (12 of 12 with grossly-resected tumor in first continuous remission). Chemotherapy achieved two partial remission among seven evaluable patients. Pediatric ASPS has a more favorable prognosis than its adult counterpart. In this series, tumor size correlates with metastatic disease at onset and is the major factor influencing survival. Surgery is the mainstay of therapy. The effectiveness of adjuvant therapy remains to be established, though radiotherapy may be advisable in cases of inadequate surgery.Annals of Oncology 12/2000; 11(11):1445-9.
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ABSTRACT: Four alveolar soft-part sarcomas were investigated by means of standard immunohistochemistry and interphase cytogenetics to further characterize the immunophenotype and proliferative activity of this tumor. The main goal of this study was to explore the chromosomal changes of this rare soft-tissue sarcoma. One epithelial (KL1), three neurogenic [neuron specific enolase (NSE), PGP 9.5, and S100], and five myogenic (desmin, myoglobin, !-smooth muscle actin, !-sarcomeric actin, and MyoD1) markers were used for the immunophenotypical analysis. Proliferative activity was assessed using the Ki67 index. Twelve (peri)centromeric (1, 3, 4, 6, 7, 8, 10, 12, 15, 17, 18, and X) and one telomeric (17q25-qtel.) chromosomal probes were used for interphase cytogenetic analysis. Three of the cases showed cytoplasmic desmin and/or myoglobin, and one showed smooth muscle actin positivity. All of the four tumors had granular, cytoplasmic, possibly nonspecific MyoD1 and sarcomeric actin positivity. Two of the tumors were positive for vimentin, four gave focal and weak staining with neurogenic markers (four of four NSE, one of four S100, and four of four PGP 9.5), but none of them was positive with KL1. Alveolar soft-part sarcomas may show myogenic immunophenotype in a number of cases, which supports myogenic differentiation. Fluorescent in situ hybridization using alpha satellite chromosomal probes revealed significant alterations in all of the cases. Most frequent and repeated numerical changes, which seem to be characteristic of the neoplasm and may play an important part in its pathogenesis and/or progression, were trisomy 7, monosomy 8 and monosomy 18.Archiv für Pathologische Anatomie und Physiologie und für Klinische Medicin 01/2001; 438(2):173-180. DOI:10.1007/s004280000332