Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029463 (osteosarcoma)
 16,637 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have examined the functional consequences of mutations present in defective alleles of the retinoblastoma susceptibility gene (RB1) isolated from two spontaneously arising tumors. Unlike cDNA clones expressing the wild-type protein p110Rb, those encoding the two mutant proteins failed to induce the appearance of senescent cells in transfected Saos-2 human osteosarcoma cells. The mutant proteins were also defective in binding to the E1A oncoprotein, were unable to become hyperphosphorylated, and failed to become tightly associated with nuclear structures. We conclude that mutations in two distinct regions of the protein concomitantly affect these four aspects of p110Rb function.
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PMID:Nonfunctional mutants of the retinoblastoma protein are characterized by defects in phosphorylation, viral oncoprotein association, and nuclear tethering. 182 60

The retinoblastoma (Rb) gene, thought by some to be associated with tumor formation of retinoblastoma as a recessive human oncogene, was investigated in 57 cases using DNA and RNA from primary osteosarcomas and other bone and soft-tissue tumors. Eight of 23 osteosarcoma cases (35%) showed structural alterations of the Rb gene. Three of the eight demonstrated homozygous deletions, and the remaining five cases showed heterozygous deletions. Seven out of eight cases represented deletion of a 7.5-kb HindIII fragment. Northern blot analysis of five cases of osteosarcoma showed that four demonstrated no detectable Rb gene transcription, and one case had a truncated 3.5-kb fragment with a faint 4.7-kb band. In the other 34 cases of bone and soft-tissue tumors, two cases of three malignant fibrous histiocytomas showed an Rb gene abnormality by Southern blot analysis. These results strongly suggest that Rb gene alteration is pertinent to the tumorigenesis of most osteosarcoma cases and some other bone and soft-tissue tumors.
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PMID:Involvement of the retinoblastoma gene in primary osteosarcomas and other bone and soft-tissue tumors. 188 49

New knowledge in cell and molecular biology has begun to expand the understanding of the biology of osteosarcoma and Ewing's sarcoma. Studies on osteosarcomas have revealed abnormalities in the growth-inhibiting retinoblastoma gene, which may release cells from normal growth control. Abnormalities in growth factor production or response tend to inappropriately activate cell growth. Tumor cell DNA content and cytogenetics may affect the diagnosis and prognostic grouping of osteosarcomas. In Ewing's sarcomas, a characteristic translocation between Chromosomes 11 and 22 has been identified; this translocation is also found in malignant neuroepitheliomas. A variety of studies point to both neuroectodermal and mesenchymal origins for Ewing's sarcomas. Applications of new biologic knowledge and technology to clinical problems will lead to significant changes in the diagnosis, and perhaps in the treatment, of these tumors in the coming years. Collaborations between community and referral center physicians and scientists are critical for continued progress.
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PMID:The cellular biology of bone tumors. 198 7

This study explores the relationship between histologic variants of bone sarcomas and previous therapy in patients in whom an unrelated malignant neoplasm had been diagnosed during childhood. Sarcomas of bone were the most common second malignant neoplasm (SMN) reported to the Late Effects Study Group, a 13-institution consortium consisting of pediatric oncology centers from western Europe, Canada, and the United States. The authors attempted to relate the histologic subtypes of the 91 bone tumors to clinical factors such as previous therapy and genetic predisposition because morphologic variants have been shown to have biologic significance in other tumors and may have etiologic import. The literature concerning the subtypes of bone tumors, clinical and experimental, is also reviewed. The authors also investigated the effect of several factors on the time interval from the first diagnosis to the SMN (i.e., the bone sarcoma). Anthracyclines significantly shortened the interval by about 3 years. The primary diagnosis also significantly affected the interval, with leukemia/lymphomas having the shortest interval and retinoblastoma the longest. The authors could not demonstrate any significant relationship between morphologic characteristics of the osteosarcoma and predisposing conditions. However, lesions diagnosed as chondrosarcoma and malignant fibrous histiocytoma occurred almost exclusively in patients who had received radiation therapy to the site in which the SMN developed.
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PMID:Bone sarcomas as second malignant neoplasms following childhood cancer. 198 16

The retinoblastoma (RB1) gene is a ubiquitously expressed gene encoding a cell-cycle control protein. Inactivation of this gene plays a crucial role in the development of retinoblastoma, osteosarcoma, and other tumors. In a search for structurally related gene sequences we identified a 5.5-kb BamHI fragment strongly cross-hybridizing with the 5' end of the RB1 cDNA. Molecular cloning, in situ hybridization, restriction mapping, and sequence analysis identified this DNA segment as the 28S rRNA gene. The absence of other cross-hybridizing sequences suggests that the RB1 gene is not part of a structurally related gene family.
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PMID:No evidence for sequences structurally related to the RB1 gene in the human genome. 199 43

Mutations of the retinoblastoma (RB1) gene are not confined to retinoblastoma, but are also involved in the development of osteosarcoma. Structural aberrations within the RB1 gene have been studied in fresh samples of eleven cases of osteosarcoma. In five cases a rearrangement was detected, one of which was best explained as a partial duplication. The chromosomal mechanisms by which the nonmutated RB1 allele was lost appeared to be similar in frequency to those that have been reported for retinoblastoma. Loss of heterozygosity was observed for chromosomes 3, 11, 13, 17, and 22. However, when no loss of heterozygosity of chromosome 13 was detected, the other chromosomes retained their heterozygosity as well. A complete association of loss of heterozygosity of chromosomes 13 and 17 was observed. This can be taken as an indication of the involvement of another tumor suppressor gene at chromosome 17 in the initiation of osteosarcoma.
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PMID:Complete association of loss of heterozygosity of chromosomes 13 and 17 in osteosarcoma. 203 39

The subcellular localization of the retinoblastoma (RB) protein has been studied in primate cell lines by immunofluorescence staining using different monoclonal and polyclonal antibodies. The protein appeared as granules of heterogeneous size over the interphase nuclei. Computer assisted digital overlap analysis indicated that it was predominantly localized in euchromatic areas with low DNA density. The largest RB positive grains lined up on the heterochromatin/euchromatin boundary. During mitosis, the RB protein dissociated from the condensing chromosomes. It was dispersed throughout the cytoplasm during metaphase and anaphase, and it reassociated with the decondensing chromatin during telophase. A new monoclonal antibody, designated aRB1C1, was raised against a bacterial TrpE/human retinoblastoma protein. It specifically recognized the nonphosphorylated and differentially phosphorylated forms of the RB protein in immunoprecipitation experiments. A collection of RB expressing cell lines gave a positive staining reaction with the antibody, whereas the RB negative Weri-RB-27 retinoblastoma and OHS osteosarcoma cells failed to react. Wild-type RB complementary DNA was introduced into Weri-RB-27 by retrovirus mediated gene transfer. Similar experiments were performed with the DU145 prostatic carcinoma cell line that expresses a mutant RB protein. Reconstituted cells of both lines expressed the normal size RB protein and gave a positive immunofluorescence reaction with the aRB1C1 and other anti-RB antibodies. The new monoclonal antibody, however, showed cell type dependent differences of the staining pattern compared to other anti-RB antibodies, suggesting differentiation dependent accessibility to its epitope.
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PMID:Subcellular localization of the retinoblastoma protein. 206 97

The product of the retinoblastoma (Rb) gene can form complexes with the transforming proteins of small DNA tumor viruses, including SV40 large T antigen (Tag), adenovirus E1A, and the human papilloma virus E7. The strong correlation between their ability to transform and their ability to bind Rb protein suggests that these oncoproteins exert their effect through blocking the Rb function. SV40 Tag causes oncogenic cell transformation of rodent cells, and it is also required for viral DNA replication. In this paper, we investigated the effect of the Rb protein on the SV40 replication associated function of Tag. We present evidence suggesting that the complex formation between Rb and Tag interferes with the viral DNA replication. In Y79 retinoblastoma and Saos-2 osteosarcoma cells, which lack functional Rb protein, a SV40 based plasmid vector, pSVEpR4, replicates well. In the same cells reconstituted for Rb expression with an intact Rb gene introduced by retroviral mediated gene transfer, pSVEpR4 replicates to a considerably lower level. The inhibitory effect of Rb protein was surmounted by increasing the intracellular level of Tag. Increasing amounts of Tag in wild-type Rb negative Y79 cells had virtually no effect on SV40 replication. Furthermore, the overexpression of Tag in Rb reconstituted Y79 cells did not alter the growth rate of the cells. These data suggest that Rb protein interacts with Tag and modulates its ability to promote SV40 DNA replication.
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PMID:Reintroduction of a normal retinoblastoma gene into retinoblastoma and osteosarcoma cells inhibits the replication associated function of SV40 large T antigen. 206 98

Between 1965 and 1988, at the Children's Hospital of Buenos Aires, 22 children developed two successive malignant tumors of different histology. The first tumor was diagnosed between 3 months and 12 years of age: 13 retinoblastoma, 2 rhabdomyosarcoma, 2 non-Hodgkin lymphoma, 2 Hodgkin disease, 1 brain stem glioma, 1 endodermal sinus tumor and 1 Ewing sarcoma. Familial cancer was registered in 6 patients. Children were treated with surgery, intensive chemo and radiotherapy. The second malignancy developed after 2 to 13 years: 10 osteosarcoma, 2 Ewing sarcoma, 2 rhabdomyosarcoma, 2 glioblastoma, 1 medulloblastoma, 1 synoviosarcoma, 1 fibrosarcoma, 1 thyroid carcinoma, 1 acute lymphoblastic leukemia and 1 acute myeloblastic leukemia. In 17 patients, the tumor developed in irradiated field. There was no evidence of the first tumor and only 1 patient was still under chemotherapy. Oncologic treatment was frustrating for these second tumors and 18 children died. Three are alive with no evidence of disease at 2 years, 2 years and 4 months and 3 years after diagnosis. One patient was lost to follow-up. It if postulated that second malignant tumors are consecutive to genetic predisposition and/or to the oncogenic effect of chemo and radiotherapy. The intensity of each treatment modality must be reduced as much as possible to obtain survival while limiting the secondary effects.
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PMID:[Second malignant tumor in children. Report of 22 cases]. 210 57

Studies were made on the appearance of second malignant tumors (SMT) in children followed in a pediatric hospital at metropolitan Santiago, Chile, between years 1968 and 1987. A retrospective analysis identified SMT in 7 of 430 patients who survived a childhood cancer (incidence 1.62%). An 8th patient was added, whose first neoplasm was treated in another hospital. The initial diagnosis in the affected children were medulloblastoma, neuroblastoma, Wilm's tumor retinoblastoma, Ewing's sarcoma, Hodgkin's disease and, in two cases, acute lymphocytic leukemias. The age range was 6 months to 11 years. Treatment was done by surgery in 5/8, chemotherapy in 7/8 and radiotherapy in all patients. The latent period between the diagnosis of the first cancer and the diagnosis of the SMT was 3.5 to 12 years (median 8.5 years). Osteosarcomas were the most frequent SMT (5/8). The other SMT were a rhabdomyosarcoma, a non Hodgkin lymphoma and an astrocytoma. The majority of SMT were located in the area of prior radiotherapy (6/8). In the other two cases, one had an osteosarcoma, after a bilateral retinoblastoma, which grew outside the previously treated area, and the last one consisted of a lymphoma which was identified 9 years after an acute lymphocytic leukemia. Only 3/8 SMT patients are alive after 14.21 and 34 months follow up. The other children died between 11 and 20 months after diagnosis of SMT. Notwithstanding these kinds of outcome, benefits of therapy for patients with primary tumors greatly outweight the later risk of cancer induction in a small proportion of them.
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PMID:[Second cancer in pediatric patients]. 213 86


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