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Trisomy 21 is a recurrent secondary aberration in childhood acute lymphoblastic leukemia with TEL/AML1 gene fusion
Author(s) -
Loncarevic Ivan F.,
Roitzheim Barbara,
Ritterbach Jutta,
Viehmann Susanne,
Borkhardt Arndt,
Lampert Fritz,
Harbott Jochen
Publication year - 1999
Publication title -
genes, chromosomes and cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.754
H-Index - 119
eISSN - 1098-2264
pISSN - 1045-2257
DOI - 10.1002/(sici)1098-2264(199903)24:3<272::aid-gcc13>3.0.co;2-u
Subject(s) - chromosomal translocation , fluorescence in situ hybridization , karyotype , trisomy , gene duplication , chromosome 21 , biology , chromosome , fusion gene , genetics , pathology , medicine , gene
TEL/AML1 gene fusion is the most frequent genetic lesion in pediatric acute lymphoblastic leukemia (ALL). It occurs as a consequence of the cryptic chromosomal translocation t(12;21)(p13;q22). In a cohort of 50 RT‐PCR–positive TEL/AML1 patients, karyotype examination by GTG banding and fluorescence in situ hybridization (FISH) allowed us to identify chromosome anomalies in addition to the already existing t(12;21). Secondary aberrations were found in 29 out of 41 patients (71%) at initial diagnosis and in all 9 patients with relapse. Structural rearrangements affected chromosome arms 2p, 2q, 5q, 9p, 12p (n = 2), 6q, 11p (n = 3), and 21q (n = 4). An extra chromosome 21 was found to be the most frequent anomaly. It was detected in 6 out of 41 patients at initial diagnosis (15%) and in 7 out of the 9 patients at relapse. No karyotype with trisomy 21 exceeded 47 chromosomes. Gain of chromosome 21 was the sole anomaly in GTG‐banding analysis in 2/41 patients at initial diagnosis and in 4/9 at relapse. Notably, chromosome painting analysis performed in 11 out of the 13 patients with an extra chromosome 21 revealed duplication of the normal chromosome 21 in 8, and duplication of der(21)t(12;21) in 3 patients. Furthermore, gain of der(21)t(12;21) chromosome was confined exclusively to the relapse patients. Genes Chromosomes Cancer 24:272–277, 1999. © 1999 Wiley‐Liss, Inc.