Gill HK1, Ten SK2, Dhaliwal JS1, Tan SK3, Roshida H3, Yasmin A4, Zubaidah Z2, Nasuruddin BA1, Yong ASM5, Chang KM5, Hishamshah 16, Eni J6, Purushotaman V5, Ho CML6
1. Immunology Division, Institute for Medical Research
2. Haematology Division, Institute for Medical Research
3. Department of Pathology, Kuala Lumpur Hospital
4. Blood Bank, Kuala Lumpur Hospital
5. Clinical Haematology Unit, Kuala Lumpur Hospital
6. Paediatric Institute, Kuala Lumpur Hospital
Correspondence: Dr Harvindar Kaur Gill, e-maiL·
CITATION: Gill HK, Ten SK, Dhaliwal JS, Tan SK, Roshida H, Yasmin A, et al. The TEL-AML1 translocation in two paediatric cases of acute lymphoblastic leukemia. International Medical Research Journal. 2000;4(1):55–61.
ABSTRACT
The TEL-AML1 translocation was detected in two paediatric cases of acute lymphoblastic leukemia. Case 14 was a three year old boy with a WBC of 5.0 x 109 /1 who was diagnosed with ALL-L1, while case 28was a five year old girl with a WBC of 22.1 x 109 /1 who was also diagnosed with ALL-L1 The karyotype of case 14 was 46XY[3] and that of case 28 was 46XX:[4]/46X:X, -5,add (9g),+mar[2]. Immunophenotyping of case 14 classified the case as CALLA-ALL with co-expression of the CD13/ CD33 myeloid antigens. RT-PCR on RNA from both cases generated a 464 hp fusion product which sequencing confirmed as the TEL gene joined to exon 2 of the AML1 gene. Case 28 also displayed a minor band of the 425 hp shorter fusion product in which the TEL gene is joined to exon 3 of the AML1 gene. A less intense band of the reciprocal AML1-TEL translocation was also detected in both cases. The presence of the fusion transcript was also confirmed by Fluorescence In Situ Hybridization (FISH). In case 14, FISH further revealed that a proportion of the cells with a TEL-AML1 fusion signal showed an associated loss of the non-translocated TEL gene.
KEYWORDS: Translocation, TEL-AML1, ALL, RT-PCR, PISH
