title: Altered expression and molecular abnormalities of cell-cycle-regulatory proteins in rhabdomyosarcoma.
abstract: Rhabdomyosarcoma is the most commonly occurring soft-tissue sarcoma in children. Some reports have discussed the altered expression and molecular abnormalities of cell-cycle-regulatory proteins in rhabdomyosarcoma; however, variable frequencies of occurrence have been noted. In the current study, among 72 cases of rhabdomyosarcoma, the authors evaluated for the expression of p53, MDM2, p16, p21/WAF1, p27, cyclin D1, cyclin E, pRb and E2F-1 protein immunohistochemically and assessed for proliferative activities using MIB-1. We also analyzed the mutation of the p53 gene in 45 cases, the amplification of the MDM2 gene in 18 cases and the mutation of the H-ras gene in 29 cases, using formalin-fixed paraffin-embedded materials. Furthermore, we assessed the correlation between clinicopathologic factors and the results of both immunohistochemical and molecular analyses. Alveolar type affected older patients, and it had a significantly higher mitotic rate compared with the embryonal type (P=0.0226). p53 overexpression was detected in 22 (30.6%) of 72 cases, and 10 (22.2%) of 45 cases had p53 gene abnormalities. As for MDM2, its overexpression was found in nine (12.5%) of 72 cases, and three (16.7%) of 18 cases showed MDM2 amplification. A statistically significant association was observed between immunoreaction for MDM2 and p53 overexpression (P=0.0002), and p53 and MDM2 overexpression was significantly correlated with high MIB-1 labeling indices. E2F-1 labeling indices showed a significantly higher score in alveolar type compared with that seen in embryonal type (P=0.0334), but MIB-1 did not. In conclusion, our study suggests that p53 overexpression may be related to tumor progression because tumors with p53 overexpression have a high proliferative activity in the current study. Alveolar type had a significantly higher both mitotic rate and E2F-1 labeling indices when compared with the embryonal type. The current study is the first report of the correlation of E2F-1 with alveolar rhabdomyosarcoma.
authors.affiliation: Department of Anatomic Pathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Takahashi
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Oda
authors.forename: Ken-Ichi
authors.initials: K
authors.lastname: Kawaguchi
authors.forename: Sadafumi
authors.initials: S
authors.lastname: Tamiya
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Sachiyo
authors.initials: S
authors.lastname: Suita
authors.forename: Masazumi
authors.initials: M
authors.lastname: Tsuneyoshi
mesh_terms: D000293:Adolescent; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000032:analysis / Q000235:genetics*; D002648:Child; D019938:Cyclin D1 / Q000032:analysis; D019927:Cyclin E / Q000032:analysis; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000032:analysis; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004252:DNA Mutational Analysis; D004273:DNA, Neoplasm / Q000737:chemistry / Q000235:genetics; D004268:DNA-Binding Proteins / Q000032:analysis; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; D005091:Exons / Q000235:genetics; D005260:Female; D005784:Gene Amplification; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis; D008297:Male; D009154:Mutation; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics; D051736:Proto-Oncogene Proteins c-mdm2; D016283:Proto-Oncogene Proteins p21(ras) / Q000032:analysis / Q000235:genetics; D016160:Retinoblastoma Protein / Q000032:analysis; D012208:Rhabdomyosarcoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D018232:Rhabdomyosarcoma, Alveolar / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D018233:Rhabdomyosarcoma, Embryonal / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D014157:Transcription Factors / Q000032:analysis; D016159:Tumor Suppressor Protein p53 / Q000032:analysis / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000032:analysis
chemical_list: D018797:Cell Cycle Proteins; D019927:Cyclin E; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004273:DNA, Neoplasm; D004268:DNA-Binding Proteins; D050684:E2F Transcription Factors; D050687:E2F1 Transcription Factor; C493753:E2F1 protein, human; D019394:Ki-67 Antigen; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D016160:Retinoblastoma Protein; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D025521:Tumor Suppressor Proteins; D019938:Cyclin D1; D050760:Cyclin-Dependent Kinase Inhibitor p27; C497206:MDM2 protein, human; D051736:Proto-Oncogene Proteins c-mdm2; D016283:Proto-Oncogene Proteins p21(ras)