Drug resistance-associated factors in primary and secondary glioblastomas and their precursor tumors

J Neurooncol. 2000 Dec;50(3):227-37. doi: 10.1023/a:1006491405010.


Malignant gliomas are largely resistant to current chemotherapeutic strategies often displaying a multidrug-resistant phenotype. Mechanisms involved in drug resistance are reduced cellular drug accumulation through membrane efflux pumps, drug detoxification as well as alterations in drug target specificity. In 27 primary and 17 secondary glioblastomas and their astrocytic precursor tumors, we studied the immunohistochemical expression profile of P-glycoprotein (P-gp), multidrug resistance-associated protein (MRP), lung resistance-related protein (LRP), metallothionein, and topoisomerase II alpha. Glial tumor cells in all glioblastomas showed constant up-regulation of LRP, MRP, and topoisomerase II alpha. P-gp was found in 90% of the primary and 60% of the secondary glioblastomas. In precursor tumors, these drug resistance-related factors were expressed in varying proportions. Metallothionein, also found in normal and activated astrocytes, was retained in all neoplastic phenotypes. Furthermore, metallothionein, P-gp, LRP, and topoisomerase II alpha were strongly expressed by normal and neoplastic vessels which may confer to impaired penetration of therapeutic agents through the blood-brain and blood-tumor barrier. However, the expression profiles of drug resistance-related proteins neither differed between primary and secondary glioblastomas nor revealed any correlation to precursor or recurrent tumors. Nevertheless, inhibition of these factors may be promising approaches to the management of malignant gliomas.

MeSH terms

  • ATP Binding Cassette Transporter, Subfamily B, Member 1 / metabolism*
  • ATP-Binding Cassette Transporters / metabolism*
  • Adult
  • Aged
  • Antibodies, Monoclonal
  • Antigens, Neoplasm
  • Antineoplastic Agents / therapeutic use
  • Brain Neoplasms / drug therapy
  • Brain Neoplasms / metabolism*
  • Brain Neoplasms / pathology
  • Brain Neoplasms / secondary
  • Cell Membrane / chemistry
  • DNA Topoisomerases, Type II* / metabolism*
  • DNA-Binding Proteins
  • Drug Resistance, Neoplasm*
  • Glioblastoma / metabolism*
  • Glioblastoma / pathology
  • Humans
  • Immunoenzyme Techniques
  • Isoenzymes / metabolism*
  • Metallothionein / metabolism
  • Middle Aged
  • Multidrug Resistance-Associated Proteins
  • Neoplasm Proteins / metabolism*
  • Vault Ribonucleoprotein Particles / metabolism*


  • ATP Binding Cassette Transporter, Subfamily B, Member 1
  • ATP-Binding Cassette Transporters
  • Antibodies, Monoclonal
  • Antigens, Neoplasm
  • Antineoplastic Agents
  • DNA-Binding Proteins
  • Isoenzymes
  • Multidrug Resistance-Associated Proteins
  • Neoplasm Proteins
  • Vault Ribonucleoprotein Particles
  • major vault protein
  • Metallothionein
  • DNA Topoisomerases, Type II