Clin Pediatr Hematol Oncol.  2014 Oct;21(2):71-79. 10.0000/cpho.2014.21.2.71.

Prevalence and Clinical Implication of Partial Tandem Duplication of the Mixed Lineage Leukemia Gene in Pediatric Acute Leukemia

Affiliations
  • 1Division of Pediatric Hemato-Oncology, Department of Pediatrics, Yonsei University College of Medicine, Yonsei University Health System, Seoul, Korea. cj@yuhs.ac

Abstract

BACKGROUND
The mixed lineage leukemia (MLL) gene may induce hematopoiesis and leukemia. Partial tandem duplication of MLL (MLL-PTD) is associated with poor prognosis in acute myeloid leukemia (AML); however, the significance of MLL-PTD in acute lymphoblastic leukemia (ALL) has not been thoroughly studied. We evaluated the incidence, relationship with other cytogenetic abnormalities, and the prognostic role of MLL-PTD in ALL.
METHODS
We reviewed medical records from pediatric patients diagnosed with ALL in Severance Hospital, Yonsei University Health System, South Korea from 2002 to 2008. MLL-PTD was detected by nested reverse transcriptase polymerase chain reaction.
RESULTS
In ALL patients, 50.0% (42/84) were positive for MLL-PTD. There was no significant difference in the 10-year overall survival (10Y OS) and event-free survival (EFS) between MLL-PTD-positive (+) and MLL-PTD-negative (-) groups (69.4% vs. 76.2%, P=0.609, and 62.6% vs. 66.7%, P=0.818, respectively). The combination of high level of lactate dehydrogenase (>1,100 IU/L) and MLL-PTD(+) [MLL-PTD(+)/High LDH] was a statistically significant negative prognostic factor for 10Y OS and EFS (P=0.0226 and P=0.0230, respectively). In multivariate analysis, National Cancer Institute risk stratification and very high risk features were independent significant prognostic factors but MLL-PTD (+)/High LDH was not.
CONCLUSION
MLL-PTD was observed frequently in pediatric ALL patients. MLL-PTD was not an independent prognostic factor. MLL-PTD (+)/High LDH should be evaluated further for its prognostic potential in ALL.

Keyword

Acute leukemia; Cytogenetics; Partial tandem duplication; MLL; Prognostic factors; Pediatric leukemia

MeSH Terms

Chromosome Aberrations
Cytogenetics
Disease-Free Survival
Hematopoiesis
Humans
Incidence
Korea
L-Lactate Dehydrogenase
Leukemia*
Leukemia, Myeloid, Acute
Medical Records
Multivariate Analysis
National Cancer Institute (U.S.)
Precursor Cell Lymphoblastic Leukemia-Lymphoma
Prevalence*
Prognosis
Reverse Transcriptase Polymerase Chain Reaction
L-Lactate Dehydrogenase
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