Molecular Genetic Studies on 167 Pediatric ALL Patients from Different Areas of Pakistan Confirm a Low Frequency of the Favorable Prognosis Fusion Oncogene TEL-AML1 (t 12; 21) in Underdeveloped Countries of the Region

Abstract

TEL-AML1 fusion oncogene (t 12; 21) is the most common chromosomal abnormality in childhood acutelymphoblastic leukemia (ALL). This translocation is associated with a good prognosis and rarely showschemotherapeutic resistance to 3-drug based remission induction phase of treatment as well as overall treatment.Thus, the higher the frequency of this fusion oncogene, the easier to manage childhood ALL in a given regionwith less intensive chemotherapy. Although global frequency of TEL-AML1 has been reported to be 20-30%,a very low frequency has been found in some geographical regions, including one study from Lahore, Punjab,Pakistan and others from India. The objective of present study was to investigate if this low frequency of TELAML1in pediatric ALL is only in Lahore region or similar situation exists at other representative oncologycenters of Pakistan. A total of 167 pediatric ALL patients were recruited from major pediatric oncology centerssituated in Lahore, Faisalabad, Peshawar and Islamabad. Patients were tested for TEL-AML1 using nestedreverse transcription polymerase chain reaction (RT-PCR). Only 17 out of 167 (10.2%) patients were found to beTEL-AML1 positive. TEL-AML1+ALL patients had favorable prognosis, most of them (82.4%, 14/17) showingearly remission and good overall survival. Thus, our findings indicate an overall low frequency of TEL-AML1in Pakistan pediatric ALL patients, in accordance with lower representation of this prognostically importantgenetic abnormality in other less developed countries, specifically in south Asia, thus associating it with poorliving standards in these ethnic groups. It also indicates ethnic and geographical differences in the distribution ofthis prognostically important genetic abnormality among childhood ALL patients, which may have a significantbearing on ALL management strategies in different parts of the world.