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TEL/AML1 rearrangement and the prognostic significance in childhood acute lymphoblastic leukemia in Hong Kong
Author(s) -
Tsang Kam Sze,
Li Chi Kong,
Chik Ki Wai,
Shing Matthew Ming Kong,
Tsoi Wai Chiu,
Ng Margaret Heung Ling,
Lau Tai Tap,
Leung Yonna,
Yuen Patrick Man Pan
Publication year - 2001
Publication title -
american journal of hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.456
H-Index - 105
eISSN - 1096-8652
pISSN - 0361-8609
DOI - 10.1002/ajh.1159
Subject(s) - immunophenotyping , incidence (geometry) , medicine , chromosomal translocation , lineage (genetic) , acute lymphocytic leukemia , cytogenetics , gene rearrangement , cohort , fusion transcript , oncology , leukemia , biology , immunology , antigen , lymphoblastic leukemia , genetics , gene , chromosome , physics , optics
The TEL/AML1 rearrangement has been implicated as an independent good prognostic factor in pediatric acute lymphoblastic leukemia (ALL). We examined TEL/AML1 using nested reverse‐transcription polymerase chain reaction (RT‐PCR) and correlated TEL/AML1 with cytogenetics and immunophenotypes in 75 consecutively analyzed Chinese children with ALL in Hong Kong. TEL/AML1 was detected in 17.9% (12/67) B‐lineage ALL at diagnosis but not in 8 T‐ALL children or in 34 adults with ALL. E2A/PBX1, MLL/AF4, and BCR/ABL were not found in TEL/AML1 + patients. Coexpression of cross‐lineage antigens was associated with TEL/AML1 gene fusion ( p = 0.032), with CD13 in 80% (4/5) TEL/AML1 + cohort. Chromosomal abnormalities were demonstrated in 50% of the TEL/AML1 + ALL; however, a cryptic t(12;21) was not detected in these cases. Hyperdiploidy of 47–48 chromosomes was encountered in 25%. Deletion of 12p resulting in the loss of the normal allele of TEL and nonspecific del(6q) were noted in 8% (1/12) and 25% (3/12) of the TEL/AML1 + children, respectively. Rapid clearance of TEL/AML1 was noted in 50% of the patients on completion of the induction therapy; however, 16.7% (2/12) TEL/AML1 + ALL relapsed at a mean of 48.6 months from diagnosis (25 months off‐therapy). The incidence of relapses of TEL/AML1 + ALL was comparable to that at diagnosis in B‐lineage ALL (14.3% [2/14] vs. 17.9% [12/67], p > 0.05). The relapse rate in TEL/AML1 + ALL was similar to that of TEL/AML1 − ALL (16.7% [2/12] vs. 20.6% [13/63], p > 0.05). The duration of first complete remission in TEL/AML1 + ALL was significantly longer as compared to TEL/AML1 − ALL (mean [range] in month: 48.6 [47.2 − 50] vs 14.6 [2.9 − 42.3], p < 0.0001). Irrespective of TEL/AML1 rearrangement, the probabilities of the five‐year overall survival and the event‐free survival of patients were comparable (overall survival: 100% vs. 72.3%, p = 0.166 and event‐free survival: 60% vs. 56.2%, p = 0.343). Our data would not suggest a less aggressive treatment regimen for TEL/AML1 + ALL. Am. J. Hematol. 68:91–98, 2001. © 2001 Wiley‐Liss, Inc.