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)

The frequency of chromosomal aberrations produced by X-rays is greater in lymphocytes cultured from trisomy 21 patients (Down's syndrome) than from normal diploid donors. This increase, which can be detected by a micronucleus assay for chromosomal damage, was postulated by us to result from a defect in the rejoining system which repairs chromosomal breaks. The postulated defect would result in a longer rejoining time, therapy permitting more movement of broken ends and thus enhancing the frequency of exchanges. To test this possibility, the time required for the rejoining (repair) of chromosome breaks was measured in lymphocytes from five Down's syndrome (four trisomy 21 and one D/G translocation partial trisomy 21) donors, from a monosomy 21 donor, and from five diploid donors. The rejoining time was reduced in the Down's syndrome lymphocytes in comparison to the normal diploid and monosomy 21 lymphocytes. Thus the repair of chromosome breaks, far from being defective as evidenced by a longer rejoining time in Down's syndrome cells, occurred more rapidly than in normal cells. A mechanism is proposed by which reduced rejoining times would increase aberration frequencies as a consequence of competition between a (hypothetical) error-free repair system and the error-prone repair system that generates chromosomal aberrations. We suggest that the alteration in the rejoining of chromosomal aberrations may underlie the increased susceptibility of people with Down's syndrome to leukemia.
 ...
PMID:The repair of X-ray induced chromosomal damage in trisomy 2-and normal diploid lymphocytes. 13 77

Among 50 cases of acute nonlymphocytic leukemia (ANLL) with available cytogenetic data seen in our section since May 1988, two were found to carry a monosomy 21 abnormality which has been rarely reported in hematologic malignancies. The first case is a 58-year-old male with a diagnosis of AML, FAB M2, who died of refractory leukemia 9 months later. The other case is a 59-year-old female with AML, FAB M2. Complete remission was achieved initially but she died of sepsis 3 months later with no evidence of leukemic relapse. Monosomy 21 is not yet recognized as a nonrandom cytogenetic abnormality in ANLL, whereas its unusual predilection in AML, especially the FAB M2 or M4 categories, as noted in our study and others' reports, have raised this possibility. Further studies and the accumulation of new cases are needed in the hope of defining it as a subtype of ANLL.
 ...
PMID:Monosomy 21 in two patients with acute nonlymphocytic leukemia. 163 89

There is a well-known raised risk of leukaemia in children with neurofibromatosis type 1 (NF-1). We carried out the first detailed population-based study of leukaemia and non-Hodgkin lymphoma (NHL) associated with NF-1 in order to estimate the risk and elucidate the relationship between these conditions. Over the 17 year study period there were five cases of chronic myelomonocytic leukaemia (CMML) in patients with NF-1 (relative risk 221; 95% CI 71-514), 12 cases of acute lymphoblastic leukaemia (ALL) (relative risk 5.4; 95% CI 2.8-9.4) and five cases of NHL (relative risk 10.0; 95% CI 3.3-23.4). Marrow cytogenetics could be reviewed for seven patients. Specific abnormalities found were monosomy 21 in a child with CMML and 7p+, 17p- in a child with ALL. No abnormalities were reported of 17q, which includes the NF1 gene. CMML occurred predominantly in boys, who also had a family history of NF-1. ALL and NHL were more often found in children with no previous family history.
 ...
PMID:Neurofibromatosis and childhood leukaemia/lymphoma: a population-based UKCCSG study. 869 73

The significance of random cytogenetic abnormalities detected in pediatric acute lymphoblastic leukemia (ALL) during remission is unknown. We studied 10 of 72 consecutive ALL patients who developed cytogenetic abnormalities during clinical remission to determine their effect on remission status. The cytogenetic abnormalities occurred at a median of 14.5 months (range 5-72) from the initial diagnosis. Five abnormalities were designated as clonal (monosomy 21 in three metaphases and 64 approximately 69,XXY in three metaphases from one patient at different times, and del(20)(q12q13) in three metaphases, add(13)(q34) in two metaphases, and ?del(19)(p11) in two metaphases from three different patients). Seven abnormalities were previously described: del(5)(q12), del(5)(q33), -7, del(11)(q23), +12, and +13 each in one metaphase, and del(20)(q12q13) in three metaphases). The remaining cytogenetic abnormalities were nonclonal and random. Flow cytometry and analysis of IgH and TcR gene rearrangements showed that all evaluable patients were in immunophenotypic and molecular remission, respectively. Eight patients remain in clinical and molecular remission a median of 9 months (range 7-18) after detecting the cytogenetic abnormality, and the leukemia in two patients has relapsed. During remission, cytogenetic abnormalities may not be a harbinger of leukemia relapse in pediatric ALL; therefore, a wait-and-see approach is prudent.
 ...
PMID:Cytogenetic abnormalities during clinical, immunophenotypic, and molecular remission in pediatric acute lymphoblastic leukemia. 1073 83