Characteristics of patients with TEL-AML1-positive acute lymphoblastic leukemia with single or multiple fusions.
BACKGROUND
The TEL-AML1 fusion in precursor-B ALL is generated by a cryptic 12;21 translocation that is detectable by fluorescence in situ hybridization (FISH). It is generally considered a favorable prognostic indicator. Some TEL-AML1+ ALL patients present at diagnosis with extra copies of the fusion, enumerated by FISH. The aim of the study was to determine whether additional copies of TEL-AML1 have clinical significance.


METHODS
Charts of all TEL-AML1+ ALL patients at the UM and Children's Hospitals and Clinics of Minnesota between 1996 and 2004 were reviewed.


RESULTS
Eight patients (7 males/1 female, mean age 46 months) with two or more TEL-AML1 fusion signals and 24 with single TEL-AML1 fusion signals (18 males/6 females, mean age 52 months) were identified. There was no statistically significant difference in age or gender between the two groups. Patients with double TEL-AML1+ had a higher frequency of myeloid markers CD13 (P = 0.04) or CD33 (P = 0.003) than single TEL-AML1+ patients. Single TEL-AML1+ patients had higher WBC (P = 0.04) than double TEL-AML1+ patients. A trend toward slower therapy response was seen in double TEL-AML1+ patients versus single, (1 of 7 [14%] <5% marrow blasts on Day 7 vs. 13 of 23 [56%], P = 0.09). Double TEL-AML1+ patients had a higher relapse rate (P = 0.09) than single TEL-AML1+ patients.


CONCLUSIONS
Utilizing FISH to distinguish subgroups of TEL-AML1 fusion patients may have important prognostic implications. The presence of an extra fusion may portend poorer prognosis. A larger and longer-term follow-up study will be required to verify the possible clinical significance of the presence of multiple TEL-AML1 fusions.
Al-Sweedan
Suleimman A
SA
Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Neglia
Joseph P
JP
Steiner
Marie E
ME
Bostrom
Bruce C
BC
Casey
Timothy
T
Hirsch
Betsy A
BA
D015703:Antigens, CD / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D018826:CD13 Antigens / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D002904:Chromosomes, Human, 21-22 and Y; D002906:Chromosomes, Human, 6-12 and X; D050676:Core Binding Factor Alpha 2 Subunit / Q000235:genetics*; D005260:Female; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007223:Infant; D007958:Leukocyte Count; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000188:drug therapy / Q000235:genetics*; D011379:Prognosis; D050783:Proto-Oncogene Proteins c-ets / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics*; D012189:Retrospective Studies; D063268:Sialic Acid Binding Ig-like Lectin 3; D014178:Translocation, Genetic; D000097764:ETS Translocation Variant 6 Protein
D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D018826:CD13 Antigens; D050676:Core Binding Factor Alpha 2 Subunit; D050783:Proto-Oncogene Proteins c-ets; D012097:Repressor Proteins; D063268:Sialic Acid Binding Ig-like Lectin 3; D000097764:ETS Translocation Variant 6 Protein; C571163:CD33 protein, human; C493728:RUNX1 protein, human