RESUMEN
Acute lymphoblastic leukemia (ALL) is characterized by recurrent clonal chromosomal abnormalities, with numerical abnormalities being a common feature especially among children. Case reports in the literature suggest that one such recurrent numerical abnormality is the gain of chromosome 5 (trisomy 5) as the sole abnormality; due to the rarity of these cases, however, little is known about their incidence, clinical features, and prognosis. We have identified seven cases with trisomy 5 as the sole or primary chromosomal abnormality from a total of 3,400 karyotypes collected in the Leukaemia Research Fund UK Cancer Cytogenetics Group Karyotype Database. All cases had a precursor B-cell immunophenotype and there was a male predominance. Five patients were children aged between 7 and 14 years old. Four of the six patients with a reasonable follow-up period had relapsed, indicating a poor prognosis. We conclude that trisomy 5 as the sole numerical abnormality occurs predominantly in older children, may be associated with a poor outcome, and may represent a distinct, albeit rare, cytogenetic subgroup in ALL.
Asunto(s)
Cromosomas Humanos Par 5 , Leucemia-Linfoma Linfoblástico de Células Precursoras/genética , Trisomía , Adolescente , Adulto , Niño , Análisis Citogenético , Femenino , Humanos , Hibridación Fluorescente in Situ , MasculinoRESUMEN
The recurrent t(14;19)(q32;q13) translocation associated with chronic B-cell lymphoproliferative disorders, such as atypical chronic lymphocytic leukemia, results in the juxtaposition of the IGH@ and BCL3 genes and subsequent overexpression of BCL3. We report six patients with B-cell precursor acute lymphoblastic leukemia who have a cytogenetically identical translocation with different breakpoints at the molecular level. Fluorescence in situ hybridization with locus-specific probes confirmed the involvement of the IGH@ gene but showed that the breakpoint on 19q13 lay outside the region documented in t(14;19)(q32;q13)-positive chronic lymphocytic leukemia. This newly described translocation constitutes a distinct cytogenetic subgroup that is confined to older children and younger adults with B-cell precursor acute lymphoblastic leukemia.
Asunto(s)
Cromosomas Humanos Par 14/genética , Cromosomas Humanos Par 19/genética , Leucemia-Linfoma Linfoblástico de Células Precursoras B/genética , Adolescente , Adulto , Niño , Femenino , Humanos , Masculino , Translocación Genética/genéticaRESUMEN
High hyperdiploidy (HeH) (51 to 65 chromosomes) is found in one third of children with acute lymphoblastic leukemia and is associated with a good prognosis. Cytogenetic features may further refine this prognosis and identify patients with a poor outcome. We examined the effect of sex, age, individual trisomies, modal number, and structural abnormalities on survival among 700 children with HeH. Univariate analysis showed that age. sex, +4, +10, +18, and a high modal number were associated with survival. Multivariate analysis however, revealed that only age, sex, +4, and +18 were independent indicators. Hazard scores for predicting relapse and mortality were constructed. Three risk groups with 5-year event-free survival (EFS) rates of 86%, 75%, and 50% (P <.0001) were identified. The high-risk group comprised boys older than 9 years, boys aged 1 through 9 years without +18, and girls older than 9 years without +18, while girls aged 1 through 9 years with +18 had the best EFS. In terms of mortality, those younger than age 10 years with both +4 and +18 had an improved survival (96% vs 84% at 5 years, P <.0001). These findings confirm that the outcome of children with HeH is heterogeneous and that specific trisomies can identify patients with the greatest and least risk of treatment failure.
