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)

Background: Mutations in members of the ras gene family (H-ras, K-ras, and N-ras) have been identified in various human malignancies. A variety of techniques have been used to test for ras mutations. Methods and Results: A simplified reverse dot blot (RDB) assay was used in this study. Polymerase chain reaction products were hybridized to nitrocellulose membrane-fixed synthetic probes (20 nucleotides long) specific for codons 12, 13, and 61 of H-, K-, and N-ras mutations and their wild-type sequences. No special treatment or modification of the probes was necessary to obtain adequate results in overnight film exposure when the polymerase chain reaction was carried out using (32)P-end labeled primers. It was demonstrated that this simplified RDB assay can also be used with fluorescein-11-dUTP and a chemiluminescence detection system. The RDB assay is more reliable than the single-strand conformation polymorphism (SSCP) assay. By comparison, the SSCP assay is significantly less sensitive and less specific. It was confirmed with sequencing that 11 (12%) of 93 SSCP assays were false positive and 2 (2%) were false negative, whereas no false positive or false negative RDB assay was detected. The RDB assay also provides more additional detailed information about the specific point mutation and amino acid change, which may have clinical implications in some tumors. Conclusions: The RDB assay is very sensitive and able to detect mutations when the mutant allele is in 1% of the cells and can be used to detect minimal residual disease, particularly in some cases of leukemia and myelodysplasia.
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PMID:Simplified Reverse Dot Blot Analyses for Detecting of ras Oncogene Mutations. 1046 6

The majority of chronic myelomonocytic leukemia (CMML) cases arise de novo; cases evolving from preexisting myelodysplasia (MDS) or myeloproliferative diseases have not been well-studied. We conducted the present study to determine the clinicopathologic features and to study possible underlying molecular and cytogenetic mechanisms involved in this evolution. Between April 1995 and November 2005, we identified 120 CMML cases, of which 20 (16.7%) had a previous diagnosis of MDS. Of the 20 patients with MDS, 6 had relative monocytosis at diagnosis. At the time of MDS to CMML evolution, mutations in JAK2 (V617F), FLT3 (ITD), K-ras-2, or N-ras were not acquired, and only 1 (6%) of 17 evaluable cases showed cytogenetic progression. The median time to evolution from MDS to CMML was 29 months, and the median survival following CMML development was 13 months. Three cases (17%) transformed to acute myeloid leukemia. These findings indicate that in some cases of otherwise typical MDS, the progenitor cells may have some capacity for monocytic proliferation at diagnosis and manifest rapid disease progression once a monocytic proliferation supervenes.
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PMID:Chronic myelomonocytic leukemia evolving from preexisting myelodysplasia shares many features with de novo disease. 1705 76

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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