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)

In acute lymphoblastic leukemia (ALL), central nervous system (CNS) prophylaxis with cranial irradiation plus 5 doses of intrathecal methotrexate (i.t. MTX) reduces the incidence of CNS relapse to 7%-15%. However, increased evidence of CNS delayed toxicity started to be recognized as CT scan abnormalities and neuropsychologic alterations, mainly in children. Two questions were analyzed in the present report: (1) Will further doses of i.t. methotrexate and dexamethasone (i.t. MTX-DMT) decrease the incidence of CNS relapse in patients treated early in remission with cranium irradiation plus i.t. MTX-DMT even more? (2) Is i.t. MTX-DMT given during induction and maintenance equally as effective as cranium irradiation plus i.t. MTX-DMT? A randomized study was designed to answer the first question. Incidence of primary CNS relapse in i.t. MTX-DMT-treated patients with a WBC count less than 50,000 was 11% (15 of 135 patients) and was 11% (17 of 150) in the untreated group. In patients with a WBC count greater than 50,000, it was 16% (6/37) in the treated group and 19% (6/31) in the control group. No difference was observed according to treatment in both prognostic groups. Patients in this study were retrospectively compared with a consecutive protocol in which patients received 3 doses of i.t. MTX-DMT alone during induction plus 3 doses weekly during the first month of remission and every 3 mo thereafter. The incidence of primary CNS leukemia at 60 mo in patients with a WBC count less than 50,000 was 20% in the irradiated group and 32% in the group with i.t. MTX-DMT alone. This difference was not significant. However, the relapse-free survival at 60 mo was 26% and 41%, respectively, (p less than 0.0005). The incidence of primary CNS relapse in patients with a WBC count more than 50,000 at 48 mo was 28% in the irradiated group and 42% in the nonirradiated group. The difference was not significant. The duration of complete remission was similar, remaining at 15% and 16% of patients disease-free at 48 mo, respectively. We conclude that (A) after cranial irradiation plus i.t. MTX-DMT X 5, the use of additional doses of i.t. MTX-DMT is not of further benefit in preventing CNS relapse; (B) the use of i.t. MTX-DMT alone compares similarly with cranial irradiation plus i.t. MTX-DMT in the incidence of CNS relapse; and (C) relapse-free survival and survival in patients with a WBC count less than 50,000 were significantly longer in those without cranial irradiation.
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PMID:Comparison of central nervous system prophylaxis with cranial radiation and intrathecal methotrexate versus intrathecal methotrexate alone in acute lymphoblastic leukemia. 657 36

The mixed lineage leukemia gene (MLL) was originally identified through its involvement in reciprocal translocations in leukemias. MLL codes for a large multidomain protein and bears homology to the Drosophila developmental control gene trithorax in two small domains in the amino terminal region, the central zinc finger domain and the carboxy SET domain. Like the Drosophila trx, MLL has also been shown to be a positive regulator of Hox gene expression. We have targeted Mll (the murine homologue of MLL) in exon 5 causing expression of three truncated in-frame Mll transcripts. These transcripts retain all or some of the AT hook motifs and the DMT domain. This mutant allele causes early in vivo preimplantation lethality of homozygous embryos prior to the 2-cell stage. Embryos cultured in vitro progress to the 2-cell stage, but further development is arrested. The heterozygotes exhibit mild skeletal defects as well as defects in some neuroectodermal derivatives.
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PMID:Truncation of the Mll gene in exon 5 by gene targeting leads to early preimplantation lethality of homozygous embryos. 1153 26