The involvement of phase I and II enzymes is well documented in the metabolism of a wide range of drugs and xenobiotics. Single-nucleotide polymorphisms (SNPs) of these enzymes are also known to alter their protein expression and function. Moreover, genetic susceptibility and environmental exposure have been proposed to be an etiology of cancer. We hypothesized that polymorphisms of these enzymes might affect the risk of childhood acute lymphoblastic leukemia (ALL). CYP 1A1, CYP 3A4*1B, CYP 3A5*3, CYP 3A5*6, GSTM1, and GSTT1 polymorphisms were genotyped by using PCR-RFLP in 107 children with ALL and 320 healthy controls. Allele and genotype frequencies of each of the SNPs were compared between two groups. It was found that the allele frequencies of CYP 1A1*1, *2A, *2B, and *4 were not different between cases and controls. CYP 3A4*1B allele frequency was only 0.8% and 0.9% in ALL and controls, respectively. CYP 3A5*1/*1, *1/*3, and *3/*3 genotype frequencies showed no statistically significant difference between patients and controls. CYP 3A5*6 was not detected in our population. The GSTM1 null genotype was significantly increased in children with ALL (OR 1.7; 95% CI, 1.0, 2.7). In contrast, the GSTT1 null genotype did not show this effect. Our data thus demonstrate that the GSTM1 null genotype might increase the risk of childhood ALL in a Thai population. Am.

1410 Poster Board I-432 INTRODUCTION: In Thailand, the prevalences of iron deficiency anemia (IDA) and thalassemia carrier are high in the range between 20-50%. Screening of both disorders may show the similar results of low hemoglobin (Hb) and mean corpuscular volume (MCV). Therefore, additional laboratory investigations such as ferritin level, percentage of iron saturation, Hb analysis and DNA study may be required for the definite diagnosis, resulting in an increased cost. Previous studies have identified several formulas to differentiate between IDA and thalassemia carrier by using red blood cell (RBC) parameters. However, individual formula may not applicable for particular population. This study aims to establish a formula to differentiae between IDA and thalassemia carrier in school-age children in central Thailand where the prevalences of β and α thalassemia carriers are high. METHODS: After informed consent, blood was collected and tested for complete blood count (CBC), ferritin level, iron level, total iron binding capacity level, Hb analysis, and DNA study for α- thalassemia-1 (or Southeast-Asian deletion). IDA was diagnosed according to the WHO criteria. Iron deficient erythropoiesis (IDE) was defined as normal hemoglobin (Hb) level and low percentage of iron saturation or ferritin levels. Subjects diagnosed of IDA and thalassemia carrier were selected for further analysis. RESULTS: Three hundred and forty-five healthy children, aged (mean±SD) 11.3±1.7 years, were enrolled in the study. The prevalences of IDA, IDE, thalassemia trait (β, a-thalassemia-1, Hb Constant Spring and HbE trait), thalassemia disease (Hb H, β/E and Hb EE), and normal subjects were 11.6%, 38.3%, 26.1%, 2.3% and 28.7%, respectively. The red blood cell (RBC) parameters of normal, IDA, IDE, HbE trait, β trait and α trait groups were shown in the table below. The median (range) values of serum ferritin level in IDA {37.3 (92.6-162.4)}, IDE {34.3 (3-268.2)} groups were significantly different when compared to normal subjects {46.9 (13.4-232.9)}, p<0.001. However, serum ferritin level alone was not enough for the diagnosis of IDA (area under ROC curve of 0.4). Various reported formulas were used to calculate the area under ROC curve, England and Fraser, 0.78; Mentzler, 0.6; Ehsani, 0.57; Shine-Lai, 0.51; RDW/RBC, 0.88; Srivastava, 0.63; RDWI, 0.79; Green and King, 0.82 and RDW, 0.69. The RDW/RBC had the highest area under ROC curve (0.88). Further analysis of the result to differentiae IDA and thalassemia carrier showed that the RDW/RBC value of ≥3 had the sensitivity and specificity of 82.4% and 88.1%, respectively, in our studied subjects. CONCLUSION: Other than the history of iron intake and thalassemia disease in the family, RDW/RBC≥3 may be an additional test to differentiate between IDA and thalassemia carrier in Thai population. In the future, the validity of this formula in a larger scale of population is recommended. Disclosures: No relevant conflicts of interest to declare.

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