Effect of polymorphisms in folate-related genes on in vitro methotrexate sensitivity in pediatric acute lymphoblastic leukemia

Robert de Jonge, Jan Hendrik Hooijberg, Bertrand D van Zelst, Gerrit Jansen, Gerritz Jansen, Christina H van Zantwijk, Christine H van Zantwijk, Gertjan J L Kaspers, Gert Jan L Kaspers, Godefridus J Peters, Frits G J Peters, Yaddanapudi Ravindranath, Rob Pieters, Jan Lindemans

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We studied whether common polymorphisms in genes involved in folate metabolism affect methotrexate (MTX) sensitivity. Ex vivo MTX sensitivity of lymphoblasts obtained from pediatric patients with acute lymphoblastic leukemia (ALL; n = 157) was determined by the in situ thymidylate synthase inhibition assay after either continuous (21 hours; TSI(50, cont)) or short-term (3 hours; TSI(50, short)) MTX exposure. DNA was isolated from lymphoblasts obtained from cytospin slides. Polymorphisms in methylenetetrahydrofolate reductase (MTHFR 677C>T, MTHFR 1298A>C), methionine synthase (MTR 2756A>G), methionine synthase reductase (MTRR 66A>G), methylenetetrahydrofolate dehydrogenase (MTHFD1 1958G>A), serine hydroxymethyl transferase (SHMT1 1420C>T), thymidylate synthase (TS 2R3R), and the reduced folate carrier (RFC 80G>A) were detected by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) or real-time PCR. Patients with the MTHFR 1298AC variant or the MTRR 66 G-allele showed decreased in vitro MTX sensitivity measured under both test conditions. SHMT1 1420TT homozygotes only showed decreased MTX sensitivity in the TSI(50, cont). In conclusion, polymorphisms in the folate-related genes MTHFR, MTRR, and SHMT1 are related to MTX resistance in pediatric patients with ALL.

Original languageEnglish
Pages (from-to)717-20
Number of pages4
Issue number2
Publication statusPublished - 15 Jul 2005


  • Antimetabolites, Antineoplastic/pharmacology
  • Child
  • Drug Resistance, Neoplasm/genetics
  • Ferredoxin-NADP Reductase/genetics
  • Folic Acid/genetics
  • Genetic Variation
  • Glycine Hydroxymethyltransferase/genetics
  • Humans
  • In Vitro Techniques
  • Methotrexate/pharmacology
  • Methylenetetrahydrofolate Reductase (NADPH2)/genetics
  • Polymorphism, Genetic
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy

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