Frequency and clinical relevance of tel-aml1 fusion gene in childhood acute lymphoblastic leukemia in Egypt

Abstract EN

TEL-AML 1 fusion gene, resulting from 12; 21 chromosomal translocation, is believed to be the most common molecular genetic abnormality in childhood acute lymphoblastic leukemia (ALL).

This study has been conducted to investigate the frequency of this fusion gene in Egyptian children suffering from ALL and to point out the different laboratory and clinical features associated with this anomaly, as well as the response of positive cases to therapy.

The status of TEL-AML1 fusion gene was determined by the reverse transcriptase polymerase chain reaction (RTPCR) in 81 children with ALL, 69 newly diagnosed and 12 in relapse.

Of the newly diagnosed cases, 7 were positive for TEL-AML1 fusion gene (10.14% of all ALL cases studied, 11.67% of precursor B ALL), as well as three out of the 12 cases (25% g all ALL cases, 30% of BCP–ALL) in relapse.

All positive cases belonged to the precursor Lineage, showed an age peak between 3 and 6 years, had non-hyper diploid DNA content and no CNS infiltration.

Most of the positive cases had total leukocytic counts below 50 x 109 / l, myeloid marker co-expression and good response to induction therapy.

In conclusion, TEL-AML1 fusion gene identifies a subset of pediatric acute lymphoblastic leukemia associated with a number of clinical and laboratory markers of good prognosis and should thus be included in routine molecular workup of acute leukemias to confirm its impact on clinical outcome and to design suitable therapeutic regimens.