Methylenetetrahydrofolate reductase (MTHFR) C677T and thymidylate synthase promoter (TSER) polymorphisms in Indonesian children with and without leukemia
Introduction
Acute lymphoblastic leukemia (ALL) is the most common malignancy that affects children, representing nearly one-third of all paediatric cancers. Annual incidence of ALL is about 30 cases per million people, with a peak incidence in patients aged 2–5 years [1]. The optimisation of the use of antileukemic agents that were developed from the 1950s through the 1980s, has resulted in a substantial reduction in death rates from ALL, particularly in children [2]. An important drug in the treatment of ALL is methotrexate (MTX), which inhibits several enzymes involved in folate homeostasis. MTX is an inhibitor of dihydrofolate reductase and decreases intracellular levels of reduced folates, such as 5,10-methylenetetrahydrofolate (CH2-THF), which is required for DNA synthesis and for maintaining the balance of the deoxynucleotide pool [3]. Methylenetetrahydrofolate reductase (MTHFR) catalyzes the reduction of 5,10-CH2-THF to 5-CH3-THF, the predominant circulatory form of folate and carbon donor for the remethylation of homocysteine to methionine (Fig. 1). MTHFR is located on the short (p) arm of chromosome 1, at position 36.3 (1p36.3). Up to 12–15% of Caucasian individuals are homozygous for a C → T polymorphism located at nucleotide 677 (referred to as the TT genotype). The resulting substitution of alanine to valine increases thermolability and reduces the activity of MTHFR [4]. Accumulation of 5,10-CH2-THF resulting from the MTHFR C677T polymorphism may have an effect on the response to MTX, and recent studies have suggested that the TT genotype may be associated with an increased toxicity of MTX in leukemia patients [5], [6]. The risk of cardiovascular disease, neural tube defects and several cancers, including ALL, may also be increased, although the evidence to support these relationships is controversial [4], [7], [8].
Thymidylate synthase (TS) is a key-enzyme in de novo DNA synthesis, which catalyses the conversion of deoxyuridine monophosphate (dUMP) to deoxythymidine monophosphate (dTMP), and is another critical target for MTX [3]. Inhibition of this enzyme results in deoxythymidine triphosphate (dTTP) depletion, chromosome breaks and cell death [9]. The TYMS gene is located on chromosome 18p11.32 and has a unique tandem repeat sequence in the enhancer region (TSER) that has been shown to be polymorphic [10], containing either two (2R) or three (3R) 28-bp repeats. The presence of the 3R versus 2R was shown to influence gene expression in vitro and in vivo[10], and in childhood ALL, homozygosity for the 3R, was reported to be associated with poorer outcome compared to the presence of at least one 2R allele [10].
The prevalence of the MTHFR C677T and TSER polymorphisms may be different among various populations and may affect the efficacy of MTX, a chemotherapeutic agent that is extensively used for the treatment of paediatric ALL. Therefore, identification of these polymorphisms may be an important pharmacogenetic determinant to predict response or toxicity to chemotherapy in children affected by leukaemia. Ethnic variations in the frequency of both the C677T MTHFR and the TSER polymorphic tandem repeat sequences have been described earlier [11], [12]. However, to our knowledge, identification of the MTHFR C677T and TSER polymorphisms in Indonesian ALL patients has not been performed before. ALL treatment protocols in Indonesia are analogous to the Dutch protocols (DCLSG ALL-6 and ALL-9), which are based on tolerability and efficacy in this Caucasian population. Since ethnic differences may exist between Dutch and Indonesian children, which may affect drug sensitivity, we determined the ethnic variations in TSER and MTHFR polymorphisms in Dutch and Indonesian children with ALL, in Dutch adult controls, and in Indonesian children without malignancies.
Section snippets
Patient and control samples
The patients of Indonesian origin included in this study were 71 children diagnosed with ALL treated at Dr. Sarjito Hospital, Yogyakarta, Indonesia and Dr. Soetomo Hospital, Surabaya, Indonesia with the Wijaya Kusuma ALL 2000 protocol. Control samples were from 44 patients without any malignancy selected within the range of 3–8 years of age, while the mean age of the children affected by ALL was 6.1 years (Table 1). For DNA isolation we used isolated mononuclear cells frozen on DMSO and stored
Results
We analyzed the TSER genotype in 71 samples of Indonesian origin from leukemia cells and compared the results to the 157 samples of Caucasian origin that were published earlier [13]. In addition, blood samples of 44 Indonesian paediatric children without any malignancies were analysed to evaluate whether the difference in genotype would be due to ethnicity and not to a characteristic of the leukaemia cells. This has for instance been described for colon cancer where occasionally only one allele
Discussion
In this paper we demonstrate that large differences exist between Indonesian and Dutch children, both in polymorphisms of TSER and MTHFR. In Indonesian children a much higher proportion of the 3R allele, and specifically of the TSER 3R/3R group, was present, while for MTHFR, the frequency of TT genotype was very low. There is no difference for TSER between Caucasian childhood ALL [13] and adult controls [12], while the genotype distribution in the Indonesian ALL samples was slightly different
Conflicts of interest
All the authors do not have any commercial or other associations that might pose a conflict of interest.
Acknowledgement
This study was supported by a grant (KWF-IN-2006-22) from the Dutch Cancer Society.
Contributions. E. Giovannetti contributed to the analysis and interpretation of data, writing the article. D.G. Ugrasena and E. Supriyadi contributed to the study conception and analysis of data. L. Vroling, A. Azzarello and D. de Lange contributed to the analysis and interpretation of data. G.J. Peters contributed to the study conception, interpretation of data, writing and revising the article. A.J.P. Veerman
References (27)
- et al.
Biological and clinical implications of the MTHFR C677T polymorphism
Trends Pharmacol Sci
(2001) - et al.
Downstream molecular determinants of response to 5-fluorouracil and antifolate thymidylate synthase inhibitors
Ann Oncol
(2000) - et al.
Influence of genetic polymorphisms on the risk of developing leukemia and on disease progression
Leuk Res
(2006) - et al.
Preponderance of methylenetetrahydrofolate reductase C677T homozygosity among leukemia patients intolerant to methotrexate
Ann Oncol
(2002) - et al.
Polymorphism of the thymidylate synthase gene and outcome of acute lymphoblastic leukaemia
Lancet
(2002) - et al.
Factor V Leiden, prothrombin 20210A, methylene-tetrahydrofolate reductase 677T, and population genetics
Mol Genet Metab
(2005) - et al.
Ethnic variation in the thymidylate synthase enhancer region polymorphism among Caucasian and Asian populations
Genomics
(1999) - et al.
Effect of polymorphisms in folate-related genes on in vitro methotrexate sensitivity in paediatric acute lymphoblastic leukemia
Blood
(2005) - et al.
The methylenetetrahydrofolate reductase 677 C → T polymorphism and preeclampsia in two populations
Obstet Gynecol
(2002) - et al.
High prevalence of the thermolabile methylenetetrahydrofolate reductase variant in Mexico: a country with a very high prevalence of neural tube defects
Mol Genet Metab
(1999)
The frequent 5,10-methylenetetrahydrofolate reductase C677T polymorphism is associated with a common haplotype in whites, Japanese, and Africans
Am J Hum Genet
Cancer statistics, 2006
CA Cancer J Clin
Treatment of acute lymphoblastic leukemia
N Engl J Med
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