Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We prospectively analyzed p15 and p16 promoter methylation patterns using methylation-specific polymerase chain reaction (PCR) in patients with adult and childhood acute leukemias and studied the association of methylation patterns with chromosomal abnormalities and prognostic variables. In nearly all French-American-British leukemia subtypes, we found p15 methylation in bone marrow or peripheral blood cells from 58% (46/79) of patients with acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), or acute biphenotypic leukemia (ABL). An identical alteration was detected in blood plasma from 11 of 12 of these patients (92%). We also demonstrated for the first time concomitant p16 and p15 methylation in 22% (8/37) of adults with AML or ALL, exclusively in those with M2, M4, or L2 subtypes. According to cytogenetic data from 35 patients with ALL, AML, or ABL, 82% (14/17) of those with unmethylated p15 alleles had normal karyotypes or hyperdiploidies associated with a favorable prognosis. Conversely, 44% (8/18) of patients with p15 methylation had chromosomal translocations, inversions, or deletions, suggesting an interplay of these abnormalities with p15 methylation. As a prognostic marker for disease monitoring, p15 methylation appears to be more widely applicable than BCR-ABL, AF4-MLL, and AML1-ETO transcripts, which were detectable in only 8% (4/48) of patients by reverse transcriptase-PCR. Thirty-nine of 43 blood samples (91%) sequentially collected from 12 patients with AML, ALL, or ABL showed p15 methylation status in excellent concordance with morphologic disease stage. Early detection of p15 methylation at apparent remission or its acquisition during follow-up may prove valuable for predicting relapse. Overall survival of patients with p15 methylation was notably shortened among 38 adults with AML and 12 adults with ALL. Aberrant p15 methylation may have important prognostic implications for clinical monitoring and risk assessment. (Blood. 2000;95:1942-1949)
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PMID:Aberrant p15 promoter methylation in adult and childhood acute leukemias of nearly all morphologic subtypes: potential prognostic implications. 1104 32

The implication of MLL gene rearrangements in the prognosis of acute myeloblastic leukemia is an issue of considerable current interest. We report a case of a young man who initially presented with a pancytopenia and went on to develop a highly-aggressive acute myeloblastic leukemia. At this time, the karyotypic study revealed trisomy 8, a t(9;11) was demonstrated by fluorescence in situ hybridization (FISH) and the MLL/AF4 rearrangement by reverse transcriptase-polymerase chain reaction (RT-PCR).
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PMID:Association of t(9;11)-MLL AF9 and trisomy 8 in an AML-M5 preceded by pancytopenia. 1094 6

Acute lymphoblastic leukemia (ALL) accounts for approximately 80% of all acute leukemias during childhood. Chromosomal anomalies resulting from gene fusion, which are frequent in leukemias, create hybrid transcripts, the great majority of which encode transcription factors. We analyzed 88 pediatric patients (median age 7.3 years) who had B-lineage acute lymphoblastic leukemia (B-ALL), using reverse transcriptase-polymerase chain reaction, to look for gene fusion transcripts of TEL/AML1, E2A/PBX1, BCR/ABL p190, and MLL/AF4. The frequencies of these transcripts were 21.21, 9.68, 3.03, and 0%, respectively. All positive cases had a common B-ALL immunophenotype. The low frequency of the TEL/AML1 transcript that is found in developing countries, such as Brazil, may be due to the low incidence of leukemia; this would support Greaves' hypothesis.
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PMID:Molecular and chromosomal mutations among children with B-lineage lymphoblastic leukemia in Brazil's Federal District. 1944 Sep 70

Contemporary protocols ensure high-remission rate and long-term free survival in children with acute lymphoblastic leukemia (ALL), but small percentage of patients is still incurable. Molecular genetic methods helped to establish submicroscopic classification as well as minimal residual disease follow-up, considered to be responsible for relapse. Our study enrolled 70 pediatric patients with de novo ALL, analyzed using reverse transcriptase-polymerase chain reaction for the presence of four major risk-stratifying translocations (BCR/ABL, MLL/AF4, TEL/AML1, and E2A/PBX1). Bone marrow samples were collected at diagnosis, at the end of induction phase, and after intensive chemotherapy with the aim to establish the correlation between chromosomal aberration, clinical features, and treatment response. Presenting the results of this study, we offer another evidence of variable incidence and clinical characteristics of ALL subtypes.
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PMID:Clinical features of the most common fusion genes in childhood acute lymphoblastic leukemia. 1948 66