Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0026986 (myelodysplastic syndrome)
 14,926 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The farnesyltransferase inhibitors (FTIs) were designed to inhibit the post-translational processing of Ras proteins, which are mutated in 30% of all human cancers. Recent studies suggest, however, that the target of FTIs may be a protein other than Ras, and that these agents may be more appropriately used to treat tumors with activated wild-type ras signaling. Preliminary results from several phase II and phase III studies have been reported. The FTIs fail to show significant single-agent activity in non-small cell lung cancer, small cell lung cancer, pancreatic cancer, refractory colorectal cancer, and bladder cancer. Activity has been shown in hematologic malignancies (acute myeloid leukemia, chronic myeloid leukemia, myelodysplastic syndrome), breast cancer, and glioma. Several combination studies of FTIs and standard cytotoxic agents are ongoing.
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PMID:Farnesyltransferase inhibitors. 1498 78

In children, myelodysplastic syndromes (MDS) represent less then 10% of all hematological malignancies; consequently, molecular genetic studies dealing with this group of patients are scarce. We have analyzed 35 archival bone marrow samples of children with MDS for the presence of mutations in the first and second exons of the NRAS and KRAS2 genes. Mutations were detected with single-strand conformation polymorphism analysis in three patients. One patient harbored a mutation in the second exon of NRAS and two patients in the second exon of KRAS2. Sequencing was performed in two samples and novel mutations were found in both. One patient had a missense mutation in codon 45 of NRAS; the other had a silent mutation in codon 53 and a missense mutation in codon 55 of KRAS2.
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PMID:Low frequency of NRAS and KRAS2 gene mutations in childhood myelodysplastic syndromes. 1547 58

Increased understanding of the cellular mechanisms associated with various malignancies has allowed researchers to develop agents that selectively target the cellular proteins and pathways implicated in the pathogenesis of malignancy. Tipifarnib is a specific and potent farnesyltransferase inhibitor that demonstrates in vivo and in vitro activity against a variety of human cancers. Although tipifarnib was initially thought to target the Ras protein, recent evidence suggests that the presence of ras mutations is not necessary for the antitumor effects of tipifarnib, and that tipifarnib may exert its effects downstream of Ras. The oral administration and favorable toxicity profile of tipifarnib, combined with its activity in a variety of intracellular pathways that have been implicated in the pathogenesis of hematologic malignancies, make it an especially attractive agent for use in patients with acute myeloid leukemia (AML), myelodysplastic syndromes, chronic myelogenous leukemia (CML), and multiple myeloma. Because hematologic malignancies are likely driven by multiple genetic aberrations, the most effective treatment strategy will likely combine multiple agents with complementary mechanisms of action. Thus, additional studies of combination regimens that incorporate tipifarnib with other antineoplastic agents are crucial. Early results from studies combining tipifarnib with imatinib or etoposide in CML and AML have been promising and warrant further evaluation in larger clinical trials.
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PMID:Farnesyltransferase inhibition in hematologic malignancies: the clinical experience with tipifarnib. 1849 98

Mutations that activate ras genes were demonstrated to be associated with certain types of malignancies. Multiple point mutations were predominantly found in the N-ras and occasionally in the K-ras genes. The analysis of 4 MDS, 23 AML and 11 CML patients from Yugoslavia revealed the prevalence of the N-ras mutation (83%) over K-ras mutations (17%). Although the frequencies of the N- and K-ras mutations in these patients were similar to the ones reported for patients from USA and Japan, the N-ras mutational spectra considerably differed. The prevailing type of mutation in patients from Yugoslavia was G-to-T transversion at the first position in the codon 12 of the N-ras gene. This study supports a hypothesis that different geographical and environmental factors may cause the accumulation of different type of point mutations in the same target gene.
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PMID:Distinct spectrum of N-ras mutations in aml and mds patients in yugoslavia. 2160 14


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