Genetic Polymorphisms of Glutathione-S-Transferase P1, T1 and M1 in Pediatric Patients with Acute Lymphocytic Leukemia in a Philippine Tertiary Hospital

Introduction. Glutathione S-transferases (GSTs) are major detoxifying

enzymes that modify susceptibility in cancers including acute

lymphocytic leukemia (ALL). This paper determines the frequency of

GST polymorphisms (M1, T1, P1) in Filipino ALL patients and control

subjects and compares the frequencies between the two groups.

Methods. Pediatric ALL patients at the UP-PGH Medical Center seen

from January to June 2007 were enrolled. Age and sex matched subjects

without ALL from the UP-PGH Outpatient Department were included

as controls. Genomic DNA was extracted from peripheral blood of

each subject. GSTM1 and T1 polymorphisms were determined using

polymerase chain reaction (PCR) while restriction fragment length

polymorphism (RFLP) analysis was employed for the determination of

GSTP1 polymorphisms. Matched Odds Ratio was used to compare the

genomic frequencies of control and ALL patients.

Results. The presence of GSTT1 and GSTM1 polymorphisms showed a

trend towards protection from having ALL, with OR 0.59 (95% CI: 0.24-

1.36) and OR 0.86 (95% CI: 0.36-2.00), respectively. Having the GSTP1

polymorphism was shown to be a risk factor [OR 1.7 (95% CI: 0.74-

4.15)].

Conclusion. Differences in GST polymorphism frequencies were

noted between the control group and ALL patients. GSTT1 and

GSTM1 polymorphisms appear protective while having the GSTP1

polymorphism confers increased risk for ALL.