Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0035412 (rhabdomyosarcoma)
 6,156 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A cell line (SCMC-MM-1) was established from a human abdominal tumor that was initially diagnosed as a malignant mesenchymoma by histological, immunohistochemical and clinical criteria. The cell line was composed of 2 morphologically and immunohistochemically distinct cell types, one with a small polygonal phenotype (P-type), characterized by the immunostaining of vimentin and the presence of a few electron-microscopically visible organelles, and the other with a giant tubular phenotype (T-type), characterized by the immunostaining of desmin, alpha-sarcomeric actin and skeletal-muscle myosin, and the presence of thick and thin myofilaments and Z-line materials. The parental cell line was cloned into 2 sublines, a P-type clone (SCMC-MM-1-19P) and a T-type clone (SCMC-MM-1-1T), which shared both 2q37 and 11p15 translocations, the characteristic chromosomal aberrations for rhabdomyosarcoma, with the parental SCMC-MM-1 cell line. Northern-blot analyses of the myogenic regulatory genes, including MyoD1 and myogenin, demonstrated the expression of MyoD1 in both of these sublines. Myogenin was very weakly expressed in the SCMC-MM-1-19P subline, but strongly expressed in the SCMC-MM-1-1T subline. Chromosomal and myogenic-regulatory-gene analyses revealed that both of these sublines were rhabdomyosarcoma cell lines. Furthermore, the regulatory-gene analyses indicated that these 2 sublines represented 2 distinct differentiation stages of myoblasts, and that MyoD1 and myogenin could serve as the lineage marker and the differentiation marker, respectively, of human rhabdomyosarcoma.
 ...
PMID:Differential expression of myogenic regulatory genes, MyoD1 and myogenin, in human rhabdomyosarcoma sublines. 131 1

Terminal differentiation of myocytes involves withdrawal from the cell cycle, induction of myogenin expression, and finally formation of myotubes. To study the factors that regulate the initial phase of muscle differentiation, we analyzed the binding activities of transcription factors AP-1, Sp-1, and NF-kappa B in L6, C2C12, and rhabdomyosarcoma BA-Han-1C cells. Temporal changes in transcription factor binding activities were compared to the activation of myogenin promoter-driven CAT reporter gene and the expression level of myogenin, a master gene of myogenic differentiation. We observed a prominent decrease in the nuclear binding activities of AP-1, Sp-1, and NF-kappa B already 12 to 24 h after the transfer of cells to differentiation medium. The response was very similar in L6 and C2C12 myocytes and in BA-Han-1C rhabdomyosarcoma cells. The down-regulation clearly preceded the activation of myogenin promoter and the induction of myogenin and retinoblastoma expression, as well as the initiation of myocyte fusion. Cholera toxin and okadaic acid, established inhibitors of myogenin expression and muscle differentiation, strongly up-regulated the binding activities of AP-1, Sp-1, and NF-kappa B in differentiation medium. Myogenin expression and myocyte fusion were also inhibited. Levels of nuclear c-Fos and c-Jun proteins, components of the AP-1 complex, showed a prominent decrease already after 12 h in differentiation medium. These results show that the down-regulation of the proliferation-promoting transcription factors is a prerequisite to the initiation of myocyte differentiation.
 ...
PMID:Down-regulation of transcription factors AP-1, Sp-1, and NF-kappa B precedes myocyte differentiation. 895 80

Alveolar rhabdomyosarcoma is an aggressive pediatric cancer of striated muscle characterized in 60% of cases by a t(2;13)(q35;q14). This results in the fusion of PAX3, a developmental transcription factor required for limb myogenesis, with FKHR, a member of the forkhead family of transcription factors. The resultant PAX3-FKHR gene possesses transforming properties; however, the effects of this chimeric oncogene on gene expression are largely unknown. To investigate the actions of these transcription factors, both Pax3 and PAX3-FKHR were introduced into NIH 3T3 cells, and the resultant gene expression changes were analyzed with a murine cDNA microarray containing 2,225 elements. We found that PAX3-FKHR but not PAX3 activated a myogenic transcription program including the induction of transcription factors MyoD, Myogenin, Six1, and Slug as well as a battery of genes involved in several aspects of muscle function. Notable among this group were the growth factor gene Igf2 and its binding protein Igfbp5. Relevance of this model was suggested by verification that three of these genes (IGFBP5, HSIX1, and Slug) were also expressed in alveolar rhabdomyosarcoma cell lines. This study utilizes cDNA microarrays to elucidate the pattern of gene expression induced by an oncogenic transcription factor and demonstrates the profound myogenic properties of PAX3-FKHR in NIH 3T3 cells.
 ...
PMID:cDNA microarrays detect activation of a myogenic transcription program by the PAX3-FKHR fusion oncogene. 1055 9

Rhabdomyosarcoma (RMS), the most common soft tissue sarcoma of childhood, displays a variety of histologic patterns. Immunohistochemistry is used extensively to distinguish RMS from its mimics. Myogenin and MyoD1, myogenic transcriptional regulatory proteins expressed early in skeletal muscle differentiation, are considered sensitive and specific markers for RMS and are more specific than desmin and muscle-specific actin and more sensitive than myoglobin. Previous studies have focused on expression of myogenin and MyoD1 in small round cell tumors. This study assesses myogenin and MyoD1 in rhabdomyosarcoma subtypes and spindle cell tumors considered in the differential diagnosis of RMS. Formalin-fixed, paraffin-embedded archival tissue from 32 RMS, 107 non-RMS, and 11 benign skeletal muscle samples was stained for myogenin and MyoD1 with standard immunohistochemical techniques. Nuclear positivity was scored on a three-tiered scale. All RMSs expressed myogenin. Alveolar RMS (ARMS) showed strong nuclear staining, especially in tumor cells lining fibrous septae and perivascular regions. In cases with a subtle alveolar architecture on routinely stained sections, myogenin highlighted and enhanced visualization of the alveolar morphologic pattern. Embryonal RMSs (ERMSs) were more variable in myogenin staining pattern and intensity. No cases of nodular fasciitis, malignant fibrous histiocytoma, malignant peripheral nerve sheath tumor, inflammatory myofibroblastic tumor, myofibrosarcoma, leiomyoma, leiomyosarcoma, or alveolar soft part sarcoma stained for myogenin. Focal nuclear reactivity was seen in desmoid (2 of 10), infantile myofibromatosis (2 of 10), synovial sarcoma (1 of 10), and infantile fibrosarcoma (2 of 10). Non-neoplastic skeletal muscle fiber nuclei stained positively for myogenin in both tumor-associated samples (25 of 40) and benign skeletal muscle samples (5 of 11). Although all RMSs were immunoreactive for MyoD1, cytoplasmic and nonspecific background staining and reactivity of nonmyoid tissues hindered its practical utility in paraffin-embedded samples in this study. Although myogenin is a highly sensitive and specific marker for RMS, it is rarely seen in other spindle cell soft tissue tumors. As previously reported, ARMS stained more strongly than ERMS. In contrast to previous studies, rare non-RMS (7 of 107) displayed focal nuclear reactivity, and entrapped atrophic or regenerative skeletal muscle fibers also stained positively. Although these are potential pitfalls in the interpretation of myogenin, careful attention to morphology and other features, to the relative paucity of myogenin-positive nuclei in non-RMS. and to the presence of entrapped muscle fibers should prevent incorrect interpretation. Because the extent of myogenin expression in RMS is much greater than in non-RMS, it is a very useful marker when interpreted in the context of other clinicopathologic data.
 ...
PMID:Are myogenin and myoD1 expression specific for rhabdomyosarcoma? A study of 150 cases, with emphasis on spindle cell mimics. 1168 74

Rhabdomyosarcomas (RMSs) are classified into embryonal (ERMS), alveolar (ARMS), and pleomorphic (PRMS) subtypes. ERMS, including botryoid variants, typically occurs in young children, ARMS typically occurs in older children and young adults, and PRMS occurs in older adults. Although ARMSs show thin fibrous bands separating nests of cells, abundant extracellular matrix production is rare in RMS. In the course of reviewing hyalinizing sarcomas we discovered a distinctive RMS in adults that closely mimicked osteosarcoma or chondrosarcoma because of the extensive matrix production. Four RMSs with hyalinized matrix were retrieved from our files. These cases were evaluated with respect to patient age and sex, tumor site and size, growth pattern, nuclear grade, cellularity, mitotic figures/20 high power fields, vascular invasion, necrosis, the presence of rhabdomyoblasts, multinucleated cells, and alveolar growth pattern. Immunohistochemistry for desmin, myogenin, MyoD1, actin, cytokeratin, S-100 protein, collagen II, and CD99 was performed. Reverse transcriptase polymerase chain reaction for the ARMS-associated PAX3/FKHR and PAX7/PKHF was also performed on three cases. The cases involved the forearm, hand, orbit, and nasopharynx of a 40-year-old woman, a 50-year-old man, an 18-year-old man, and a 21-year-old man, respectively. The tumors ranged from 3.7 to 8 cm and consisted of lobules and infiltrating cords of small round malignant cells embedded in a densely hyalinized matrix having both a chondroid and osteoid-like appearance. No definite lacunae or matrix calcification was present. An alveolar pattern was only present focally, and tumor giant cells were not present. One case had a single focus of rhabdomyoblastic differentiation with strap cells. Mitotic activity was >20 mitotic figures/20 high power fields in three of four cases. Immunohistochemically, one case strongly expressed desmin, whereas three cases expressed it focally, with a dot-like pattern. Myogenin was only focally positive, but MyoD1 was present in nearly every cell of each case. Two cases expressed actin and one expressed CD99. No case expressed cytokeratin, S-100 protein, or collagen II. Only one case contained adequate RNA for reverse transcriptase polymerase chain reaction, and this case was negative for the ARMS-associated gene fusions. Follow-up showed one patient to be dead of metastatic disease at 60 months despite intensive therapy, another patient to be disease free at 26 months, and the third patient to be disease free at 5 months. The fourth case is recent. These cases are a distinctive-appearing rhabdomyosarcoma easily mistaken for variants of chondrosarcoma, osteosarcoma, or even sclerosing epithelioid fibrosarcoma because of their hyalinizing appearance compounded by their typically focal and dot-like desmin expression. These four cases are essentially identical to the three unusual RMSs recently reported by Mentzel and Katenkamp as "sclerosing, pseudovascular rhabdomyosarcoma in adults." Although the focal alveolar architecture and the primitive cytologic appearance of these hyalinizing RMS suggest a relationship with ARMS, the presence of abundant strap cells in one case, the predominant expression of MyoD1 rather than myogenin, and the absence of ARMS-associated fusions genes point more strongly toward a variant of ERMS. However, the late adult age in two cases is unusual for both EMRS and ARMS, suggesting that sclerosing RMS may prove to be a distinct subtype of RMS. Study of additional cases will be necessary to more fully elucidate its place among RMS and its prognostic significance.
 ...
PMID:Sclerosing rhabdomyosarcoma in adults: report of four cases of a hyalinizing, matrix-rich variant of rhabdomyosarcoma that may be confused with osteosarcoma, chondrosarcoma, or angiosarcoma. 1221 74

Myogenin and MyoD regulate the development of skeletal muscle, and their expressions are specific to the stages of myogenesis. Therefore, these myogenic regulatory proteins could be considered as sensitive and specific markers for rhabdomyosarcoma. In this report we investigated the immunohistochemical reactivities of myogenin and MyoD in two canine bladder botryoid rhabdomyosarcomas that were different in the degree of differentiation. MyoD was stained in the Ki-67 antigen-positive undifferentiated mesenchymal cells, which had proliferative activity similar to myoblasts differentiated from mesoblasts. In contrast, multinucleated neoplastic cells were positive for myogenin and alpha-sarcomeric actin but not for Ki-67 antigen, similar to the myotubes differentiated from myoblastic cells. The expressions of myogenin and MyoD were closely correlated to the histologic features of myogenic neoplastic cells.
 ...
PMID:Expression of myogenic regulating factors, Myogenin and MyoD, in two canine botryoid rhabdomyosarcomas. 1513 78

Immunohistochemistry remains the current ancillary method of choice in the pathologic evaluation of small blue round-cell tumors. In at least 20% of cases of rhabdomyosarcoma (RMS), it is considered an essential factor in the final and/or differential diagnosis of the malignancy. Newer immunostains (antimyogenin, MyoD1) generated against intranuclear myogenic transcription factors offer pathologists the best hope for improving the sensitivity and specificity of RMS diagnosis. A large series of RMS (956) were studied consecutively from the intergroup rhabdomyosarcoma study and children's oncology group files, along with multiple other malignant, benign or reactive lesions. A panel of antibodies to muscle-related antigens (myogenin, MyoD1, desmin, muscle-specific actin) was studied using formalin-fixed, paraffin-embedded tissue, an avidin-biotin/peroxidase complex immunohistochemical technique, antigen retrieval technique as appropriate, and automated immunostaining. Myogenin and MyoD1 were equally sensitive (positive for 97% of RMS cases), with both also showing similar specificity (90% vs. 91% of cases) for the diagnosis of RMS. Myogenin and MyoD1 staining were sometimes intact in areas of coagulative tumor necrosis, but negated by B5 fixation. Isolated, rare benign myogenin-positive nuclei were seen infrequently in reactive lymph nodes. Specifically, both myogenin and MyoD1 had significantly greater extent of expression for alveolar RMS (ARMS) than embryonal RMS (ERMS) (both with P < 0.001). Similarly, both myogenin (P = 0.001) and MyoD1 (P < 0.001) had significantly higher expression for ARMS than RMS, not otherwise specified (NOS). They were never expressed in undifferentiated sarcomas; however, reactive or regenerative myocytes did show expression. Immunostains against intranuclear myogenic transcription factors are, at present, the best available markers for confirming the diagnosis of RMS. Their differential expression in reactive myogenic lesions, variability in ARMS versus ERMS, and absence in undifferentiated sarcomas suggest new biologic questions to be explored in future studies.
 ...
PMID:An immunohistochemical algorithm to facilitate diagnosis and subtyping of rhabdomyosarcoma: the Children's Oncology Group experience. 1686 66

Morphologically, the distinction between undifferentiated embryonal sarcoma of the liver (UESL) and biliary tract rhabdomyosarcoma (RMS) can be uncertain because of some shared pathologic similarities. Patients with UESL have been consistently but erroneously enrolled in Children's Oncology Group (COG) treatment protocols because UESL was equated with RMS, despite the differing primary treatment modalities of these entities. Review of COG pathology files yielded 20 cases of UESL that were compared to 25 cases of biliary tract RMS. Clinicopathologic features including immunohistochemical staining were examined. In the UESL cases, the male:female ratio was 1:1 and the median age was 10.5 years. Histologically, hyaline globules and diffuse anaplasia were consistently present. The cases of RMS had a male:female ratio of 1.8:1 with a median age of 3.4 years and routinely lacked diffuse anaplasia and hyaline globules. Polyclonal desmin and muscle-specific actin were variably immunoreactive in UESL and RMS; however, myogenin and myogenic regulatory protein D1 (MyoD1) were uniformly negative in UESL and routinely positive in the majority of biliary tract RMS. Myogenin, in particular, was highly significant (P = 0.0003) in distinguishing RMS from UESL. With a median follow-up of 8 months, 11 of 18 patients with UESL were still alive. The estimated 5-year survival for biliary tract RMS was 66%. Establishing the correct diagnosis of these distinct clinical and pathologic entities is important, as surgery alone may be curative in UESL, whereas initial chemotherapy is often recommended for the treatment of biliary tract RMS.
 ...
PMID:Distinguishing undifferentiated embryonal sarcoma of the liver from biliary tract rhabdomyosarcoma: a Children's Oncology Group study. 1737 82

Myogenin and its upstream regulator MyoD are known to be required for myogenic cell differentiation. Although both of them can be expressed in rhabdomyosarcoma-derived RD cells, the cells are unable to undergo full-scale terminal myogenic differentiation. 12-O-Tetradecanoylphorbol-13-acetate (TPA) has been found to be functional in the induction of RD cell differentiation, whereas its mechanism is not fully understood. By using quantitative real-time-based chromatin immunoprecipitation and real-time reverse transcription-PCR-based promoter activity assays, we examined the activation mechanism of the myogenin gene during TPA-induced differentiation of the RD cells. We have shown that a histone acetyltransferase PCAF and ATPase subunit BRG1 of the SWI/SNF chromatin remodeling complex are sequentially recruited to the promoter of the myogenin gene. Both PCAF and BRG1 are also involved in the activation of the myogenin gene. In addition, we have found that the p38 mitogen-activated protein kinase is required for BRG1 recruitment in TPA-mediated myogenin induction. We propose that there are two distinct activation steps for the induction of myogenin in TPA-induced early differentiation of RD cells: 1) an early step that requires PCAF activity to acetylate core histones and MyoD to initiate myogenin gene expression, and 2) a later step that requires p38-dependent activity of the SWI/SNF remodeling complex to provide an open conformation for the induction of myogenin. Our studies reveal an essential role for epigenetic regulation in TPA-induced differentiation of RD cells and provide potential drug targets for future treatment of the rhabdomyosarcoma.
 ...
PMID:Sequential recruitment of PCAF and BRG1 contributes to myogenin activation in 12-O-tetradecanoylphorbol-13-acetate-induced early differentiation of rhabdomyosarcoma-derived cells. 1746 5

Myogenin immunostaining has been described as a useful marker of the alveolar subtype of rhabdomyosarcoma and as a tool for distinguishing it from the more common embryonal subtype. To add to the growing body of literature describing this phenomenon we analysed myogenin immunohistochemical staining in 152 tumors using a rhabdomyosarcoma tissue array. Results were analysed blinded to histological type by two independent investigators. Samples were excluded if any samples failed to stain with desmin and/or myogenin. Mean percentage of myogenin positive cells was significantly greater for ARMS (n = 31; mean percentage positivity 59% (95% confidence intervals +/- 7%) than ERMS (n = 41, mean percentage positivity 16%, 95% confidence intervals +/- 4; P < 0.0001). This data is consistent with previously published studies identifying strong nuclear myogenin staining in a high proportion of cells as a marker of alveolar histology.
 ...
PMID:Rhabdomyosarcoma subtyping by immunohistochemical assessment of myogenin: tissue array study and review of the literature. 1849 75


1 2 3 Next >>