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)

It has become clear that several polymorphisms of human drug-metabolizing enzymes influence an individual's susceptibility for chemical carcinogenesis. This review gives an overview on relevant polymorphisms of four families of drug-metabolizing enzymes. Rapid acetylators (with respect to N-acetyltransferase NAT2) were shown to have an increased risk of colon cancer, but a decreased risk of bladder cancer. In addition an association between a NAT1 variant allele (NAT*10, due to mutations in the polyadenylation site causing approximately two fold higher activity) and colorectal cancer among NAT2 rapid acetylators was observed, suggesting a possible interaction between NAT1 and NAT2. Glutathione S-transferases M1 and T1 (GSTM1 and GSTT1) are polymorphic due to large deletions in the structural gene. Meta-analysis of 12 case-control studies demonstrated a significant association between the homozygous deletion of GSTM1 (GSTM1-0) and lung cancer (odds ratio: 1.41; 95% CI: 1.23-1.61). Combination of GSTM1-0 with two allelic variants of cytochrome P4501A1 (CYP1A1), CYP1A1 m2/m2 and CYP1A1 Val/Val further increases the risk for lung cancer. Indirect mechanisms by which deletion of GSTM1 increases risk for lung cancer may include GSTM1-0 associated decreased expression of GST M3 and increased activity of CYP1A1 and 1A2. Combination of GST M1-0 and NAT2 slow acetylation was associated with markedly increased risk for lung cancer (odds ratio: 7.8; 95% CI: 1.4-78.7). In addition GSTM1-0 is clearly associated with bladder cancer and possibly also with colorectal, hepatocellular, gastric, esophageal (interaction with CYP1A1), head and neck as well as cutaneous cancer. In individuals with the GSTT1-0 genotype more chromosomal aberrations and sister chromatid exchanges (SCEs) were observed after exposure to 1,3-butadiene or various haloalkanes or haloalkenes. Evidence for an association between GSTT1-0 and myelodysplastic syndrome and acute lymphoblastic leukemia has been presented. A polymorphic site of GSTP1 (valine to isoleucine at codon 104) decreases activity to several carcinogenic diol epoxides and was associated with testicular, bladder and lung cancer. Microsomal expoxide hydrolase (mEH) is polymorphic due to amino acid variation at residues 113 and 139. Polymorphic variants of mEH were associated with hepatocellular cancer (His-113 allele), ovarian cancer (Tyr-113 allele) and chronic obstructive pulmonary disease (His-113 allele). Three human sulfotransferases (STs) are regulated by genetic polymorphisms (hDHEAST, hM-PST, TS PST). Since a large number of environmental mutagens are activated by STs an association with human cancer risk might be expected.
 ...
PMID:Polymorphisms of N-acetyltransferases, glutathione S-transferases, microsomal epoxide hydrolase and sulfotransferases: influence on cancer susceptibility. 1002 93

Double minute chromosomes (dmin) are small chromatin bodies consisting of genes amplified in an extrachromosomal location. dmins are uncommon in hematologic malignancies; they are seen primarily in acute myeloid leukemia, with amplification of the MYC oncogene or, less frequently, the MLL transcription factor. Nine patients with hematologic malignancies with dmin were seen at the Roswell Park Cancer Institute between 1985 and 2000; eight had acute myeloid leukemia and one a myelodysplastic syndrome. Fluorescence in situ hybridization (FISH) demonstrated MYC amplification on dmin in four patients, but MLL amplification was not seen. Spectral karyotyping showed that the dmin derived from chromosome 11 in one patient and from chromosome 19 in two others without MYC or MLL amplification; derivation from these chromosomes was confirmed by FISH with chromosome paint probes. The dmin of chromosome 11 origin hybridized to a bacterial artificial chromosome (BAC) RP11-112M22 that maps to 11q24.3 and is predicted to contain ETS1 and other markers, including D11S11351 and D11S4091. The dmin of chromosome 19 origin in one patient hybridized to BACs RP11-46I12 and RP11-110J19; in the other patient, these clones did not hybridize with the dmin, but were found to be amplified on a marker chromosome that was derived from chromosome 19 in that patient's cells. These BACs have been mapped to 19q12-19q13.1 and 19q11-19q13.1, respectively, and are predicted to contain the markers D19S409 and D19S919 and the gene for ubiquinol-cytochrome C reductase, Rieske iron-sulfur polypeptide1 (UQCRFS1). dmin originating from chromosome 19 have not been reported previously in hematologic malignancies.
 ...
PMID:Double minute chromosomes in acute myeloid leukemia and myelodysplastic syndrome: identification of new amplification regions by fluorescence in situ hybridization and spectral karyotyping. 1192 Dec 81

The Myelodysplastic Syndromes are stem cell heterogeneous disorders characterized by peripheral cytopenias and hypercellular bone marrow, which can evolute to acute leukaemia. Vitamin C can act as an antioxidant, ascorbic acid (AA) donates two electrons and becomes oxidized to dehydroascorbic acid (DHA). Under physiological conditions, vitamin C predominantly exists in its reduced (AA) form but also exists in trace quantities in the oxidized form (DHA). This study evaluates the therapeutic potential of vitamin C in Myelodysplastic Syndromes (MDSs). F36P cells (MDS cell line) were treated with ascorbate and dehydroascorbate alone and in combination with cytarabine. Cell proliferation and viability were assessed by trypan blue assay and cell death was evaluated by optical microscopy and flow cytometry. The role of reactive oxygen species, mitochondrial membrane potential, BAX, BCL-2 and cytochrome C were also assessed. Vitamin C decreases cell proliferation and viability in a concentration, time and administration dependent-manner inducing cell death by apoptosis, which was shown to be associated to an increased in superoxide production, mitochondrial membrane depolarization. These compounds modulate BCL-2, BAX and cytochrome C release. These results suggest that vitamin C induces cell death trough apoptosis in F36P cells and may be a new therapeutic approach in Myelodysplasia.
 ...
PMID:Oxidative stress mediates apoptotic effects of ascorbate and dehydroascorbate in human Myelodysplasia cells in vitro. 2354 9