Resistance mechanisms to methotrexate in tumors

J. R. Bertino, E. Göker, R. Gorlick, W. W. Li, D. Banerjee

Research output: Contribution to journalArticlepeer-review

45 Scopus citations


The mechanisms of intrinsic and acquired resistance to methotrexate (MTX) in human tumors are reviewed herein. In blasts from patients with acute lymphocytic leukemia, resistance mechanisms found are decreased uptake and increased dihydrofolate reductase (DHFR) activity. A major cause of intrinsic resistance to MTX in soft tissue sarcoma cells and in acute myelocytic leukemia appears to be a lack of drug retention, due mainly to low levels of polyglutamylation. A novel association between lack of the retinoblastoma protein and intrinsic MTX resistance has been found. This has been attributed to an increase in DHFR activity, due to an increased rate of transcription of this gene, stimulated by an increase in levels of free E2F, not sequestered by hypophosphorylated retinoblastoma protein.

Original languageEnglish (US)
Pages (from-to)223-226
Number of pages4
Issue number4
StatePublished - 1996
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Oncology
  • Cancer Research


  • Dihydrofolate reductase
  • Drug resistance
  • Folylpolyglutamate synthetase γ-glutamyl hydrolase
  • Leukemia
  • Methotrexate
  • Sarcoma
  • Trimetrexate


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