Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A search of the records of 10 pediatric oncology centers revealed 102 children with more than one malignant neoplasm. In this group of 102 patients, all pediatric cancers were seen as initial lesions, but Wilms' tumor and retinoblastoma were over-represented and leukemia and brain tumors underrepresented. Survival variation as well as tumor susceptibility may be responsible for this disproportion. Osteosarcomas and chondrosarcomas were the most frequent second malignant neoplasms (SMN). Embryonal tumors were rare as SMN and adult-type tumors (carcinomas) appeared at earlier than expected ages, whether arising after irradiation or not related to that form of therapy. Radiation was associated with 69 SMN, genetic disease accounted for 27 SMN and both conditions were noted in 15 SMN. In the group of 21 patients for whom neither radiation nor a known genetic disorder could be implicated, there were three with colon carcinoma and glioma and five with leukemia or lymphoma and glioma. These combinations may reflect new tissue-specific hereditary cancer syndromes.
 ...
PMID:Patterns of second malignant neoplasms in children. 19 10

Neuroblastoma is an embryonal tumor originating from neural crest-derived cells. Here we present the serendipitous cloning of amplified sequences of chromosome 2p15 in neuroblastoma cell line IMR32. The amplified region was analyzed for oncogene activation using a SAGE (serial analysis of gene expression) library of IMR32. SAGE permits a quantitative analysis of all transcripts of a tissue or cell line. The expression of genes and ESTs mapping within a 30-cR region covering the amplicon was compared to 4 additional SAGE libraries of neuroblastomas and 12 SAGE libraries of other tissues in the CGAP databases. The IMR32 SAGE database revealed increased expression of the MEIS1 oncogene, whereas other SAGE libraries showed little or no MEIS1 expression. MEIS1 turned out to be highly amplified and overexpressed in IMR32. Analysis of 24 neuroblastoma cell lines and 22 tumors showed high-level expression in about 25% of the cases. The MEIS1 homeobox protein forms a complex with the HOXA9 and PBX proteins that are implicated in human leukemia. MEIS1 is a target of retroviral insertion in murine leukemia. This is the first report of a MEIS1 amplification and high expression levels in human cancer and the first time that identification of a candidate target of amplification is facilitated by high-throughput mRNA expression profiling.
 ...
PMID:The MEIS1 oncogene is highly expressed in neuroblastoma and amplified in cell line IMR32. 1116 15

Significant progress has been made in understanding the molecular basis of pediatric malignancies. Mechanisms of pediatric acute leukemia induction include hyperdiploidy, aberrant expression of proto-oncogenes, and activation of transcription factors or kinases by aberrant fusion genes. Molecular analysis of these alterations has facilitated the recognition of distinct groups with different sensitivity to therapy, and identified potential targets for antileukemic agents. Similar analysis of pediatric soft tissue and bone tumors also resulted in the identification of specific fusion genes, and their characterization has contributed greatly to understand their biology. Molecular assays for these rearrangements have become important tools in classifying these tumors, providing important prognostic data. However, the understanding of mechanisms involved in the pathogenesis of many other pediatric malignancies, including some embryonal tumors--believed to arise due to perturbation of the normal developmental program--is still vastly incomplete. The Department of Pathology at Texas Children's Hospital is one of the Children's Oncology Group (COG) reference centers for pediatric liver tumors. We have been particularly interested in the biology of hepatoblastoma, the most common type of pediatric liver tumor. Although a number of cytogenetic and molecular abnormalities have been described for this type of embryonal tumor, its pathogenesis is still poorly understood. In an attempt to explore the role of different signaling pathways in this disease, we analyzed the expression patterns of different histologic subtypes of hepatoblastoma using cDNA microarray analysis, qualitative reverse transcription, polymerase chain reaction (QRT-PCR), and immunohistochemistry. Wnt signaling pathway, critical both in development and in neoplasia, appears to be particularly relevant in these tumors. Mutations of the beta-catenin gene are present in over 90% of hepatoblastomas, leading to activating transcription of a number of target genes. The pattern of beta-catenin expression and type of mutation in groups of tumors are crucial to understand the corresponding differences in their gene expression profiles. Our findings are consistent with a relationship between poor histologic phenotype and beta-catenin activation, indicating the potential utility of targeted gene expression assays to identify molecular events related to the pathogenesis and prognosis of hepatoblastomas. Integration of clinical, morphologic, phenotypic, cytogenetic, and molecular data has become the basis of novel prognostic prediction and therapeutic strategies in pediatric leukemia. Similarly, integration of new genetic and molecular data with clinical, and other diagnostic information will be crucial for accurate classification of pediatric tumors, risk stratification, and successful development of new therapies for pediatric oncologic patients.
 ...
PMID:Integrating the diagnosis of childhood malignancies. 1716 62

Embryonal cancer can arise from postnatally persistent embryonal remnant or rest cells, which are uniquely characterized by the absence of p53 mutations. Perinatal overexpression of the MycN oncoprotein in embryonal cancer precursor cells causes postnatal rests, and later tumor formation through unknown mechanisms. However, overexpression of Myc in adult tissues normally activates apoptosis and/or senescence signals as an organismal defense mechanism against cancer. Here, we show that perinatal neuroblastoma precursor cells exhibited a transiently diminished p53 response to MycN oncoprotein stress and resistance to trophic factor withdrawal, compared with their adult counterpart cells from the TH-MYCN(+/+) transgenic mouse model of neuroblastoma. The adult stem cell maintenance factor and Polycomb group protein, Bmi1 (B-cell-specific Moloney murine leukemia virus integration site), had a critical role at neuroblastoma initiation in the model, by repressing p53 responses in precursor cells. We further show in neuroblastoma tumor cells that Bmi1 could directly bind p53 in a complex with other Polycomb complex proteins, Ring1A or Ring1B, leading to increased p53 ubiquitination and degradation. Repressed p53 signal responses were also seen in precursor cells for other embryonal cancer types, medulloblastoma and acute lymphoblastic leukemia. Collectively, these date indicate a general mechanism for p53 inactivation in some embryonal cell types and consequent susceptibility to MycN oncogenesis at the point of embryonal tumor initiation.
...
PMID:Direct effects of Bmi1 on p53 protein stability inactivates oncoprotein stress responses in embryonal cancer precursor cells at tumor initiation. 2290 36