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Prognostic importance of structural chromosomal abnormalities in children with hyperdiploid (greater than 50
C H Pui1, S C Raimondi, R K Dodge
1Department of Hematology-Oncology, St Jude Children's Research Hospital, Memphis, TN 38101.
Insights
Children with hyperdiploid acute lymphoblastic leukemia (ALL) and structural chromosomal abnormalities face a higher risk of treatment failure. This finding highlights a distinct subtype of ALL that may be more resistant to therapies.
Area of Science:
- Pediatric Oncology
- Clinical Genetics
- Hematology
Background:
- Hyperdiploid acute lymphoblastic leukemia (ALL), characterized by >50 chromosomes, typically has a favorable prognosis in children.
- Despite this, a significant number of pediatric patients with hyperdiploid ALL experience treatment failure.
- Identifying predictive factors for treatment failure is crucial for improving outcomes.
Purpose of the Study:
- To investigate initial clinical and cytogenetic features associated with treatment failure in children with hyperdiploid ALL.
- To determine if the presence of structural chromosomal abnormalities impacts treatment outcomes in this patient group.
Main Methods:
- Retrospective analysis of 138 children diagnosed with hyperdiploid ALL (>50 chromosomes).
- Evaluation of initial clinical data and cytogenetic features, specifically focusing on numeric and structural chromosomal abnormalities.
- Statistical analysis, including Breslow test and multivariate analysis, to identify predictors of treatment failure.
Main Results:
- Of 138 children, 85 (62%) had co-existing structural chromosomal abnormalities.
- Treatment failure occurred in 22 of the 28 cases with structural abnormalities (P = .03).
- Multivariate analysis identified structural chromosomal abnormalities and male gender as independent predictors of treatment failure.
Conclusions:
- Structural chromosomal abnormalities in pediatric hyperdiploid ALL are associated with a higher likelihood of treatment failure.
- These findings suggest that hyperdiploid ALL with structural abnormalities may represent a distinct biological subtype with increased drug resistance.
- Further research into targeted therapies for this subgroup is warranted.
Abstract:
Approximately one fourth of children with newly diagnosed acute lymphoblastic leukemia (ALL) have hyperdiploid (greater than 50 chromosomes) blasts and a relatively favorable prognosis. Nonetheless, a substantial proportion of these patients fail therapy. We studied 138 children (70 male, 68 female) with hyperdiploid greater than 50 ALL to assess initial clinical and cytogenetic features that might predict treatment failure. In 85 of these cases (62%), structural chromosomal abnormalities were also present; clinical and laboratory features in this group did not differ from those of the 53 cases with only numeric abnormalities. However, of the 28 failures seen at a median follow-up of 4 years, 22 occurred in cases with structural chromosomal abnormalities (P = .03 by Breslow test). In a multivariate analysis, only the presence of structural chromosomal abnormalities and male gender were independently associated with treatment failure. Structural chromosomal abnormalities in cases of ALL with greater than 50 chromosomes may define a biologically different form of leukemia characterized by increased likelihood of drug resistance.